It’s barely been a month since the iPhone update which allows people to download applications written by 3rd-party developers, and there are already more than 1,000 to choose from. Here are a few of the more promising entries in the field of Personal Finance:

Loan Shark

(Web | iTunes)

It’s unreasonable to expect that a person, when presented with a loan offer, can glance at the numbers and determine whether the salesperson is trying to rip them off. If it hadn’t happened to a friend of mine, I might’ve chalked this scenario up to simple paranoia, but it does happen. Thankfully, what with the Internet empowering us all, it happens less and less.

If all you’re looking to do is check the math on a loan offer, there are other ways to go about it. For example, you could point your mobile browser to CalcNexus’s Auto Loan Calculator and get an answer pretty quickly. The major advantage to the Loan Shark iPhone app is that it saves loan details to a Favorites screen so you can compare offers from different banks.

It also shows amortization tables and works as well for credit cards and home loans. For my money, in this case US$4.99, that’s a lot more convenient than carrying around a notepad and a pen.

Save Benjis

(Web | iTunes)

At some point (for me this happens weekly), you’ve been in a store, looking at something you probably want to buy, and you thought to yourself, “I could get this cheaper somewhere else.” Save Benjis answers your doubts for you in a matter of seconds. Best of all, it’s free, so you have nothing to lose if you want to give it a try.

Pick & Choose – Groceries

(Web | iTunes)

“Okay, I’m at Target. What was that other thing I needed to buy?” The analog lifestyle solution to this conundrum was always to keep a shopping list on the fridge and take it with you. But more often than not, I’m coming straight from work, or I forgot the list at home.

You may have noticed by now that I have a sort of contempt for paper records. Anyway…

This app has a built-in database of over 1,500 grocery items, so you barely need to type anything. In fact, I think I’m going to buy this app right now.

Lately I’ve noticed commercials for a special car buying incentive offered by Chrysler: a gas credit card that guarantees that you will pay no more than $2.99 for a gallon of gas for three years. The offer, good between now and June 2 on most Chrysler, Jeep and Dodge vehicles preys on our fear and anticipation of higher gas costs this coming summer.

But the numbers don’t work out all that well. First, in order to qualify for the $2.99 gas card, which is good for regular unleaded gasoline, diesel, or E85, you must relinquish your option to take advantage of any other purchasing incentive. Assuming the average gas price over the next three years is $3.99, and it could be lower once the political environment changes, one might save a couple hundred dollars a year. But how is this worthwhile if you have to give up a $2,000 (or more) cash back deal to qualify? A quick search of Chrysler incentives shows that dealers are offering up to $3,000 cash back. In other locations offering you can find incentives offering $5,000 cash back.

Additionally, according to the rules of this “Let’s Refuel America” incentive, your gas savings would be limited to 12,000 miles a year. After that limit, you would have to pay full price.

It makes no sense to give up a $5,000 discount in return for the possibility of saving a few hundred dollars a year. Keep in mind that three years from now, the price of gas may be much less than $2.99. You would have given up a significant incentive for very little benefit.

The perceived savings on the cost of gas is higher than the numbers reveal. Chrysler is simply seizing the opportunity to present a deal that looks nice to customers concerned about rising gas costs, but this deal is much better for the dealer than for the buyer.

If you’re concerned about gas savings and you’re in the market for a new car, opting for a vehicle with just a little more fuel efficiency compared to the Chrysler cars and trucks will be a better option for saving money on gas. Just a 3 mpg improvement will save $3,000 in the first three years, and then would continue saving money long beyond the expiration of the terms of this deal.

Photo credit: joebeone

If you’re looking for bonus points or miles with your credit cards (and I would only suggest doing so if you pay your credit card balances in full every month and if you travel frequently), CitiBank is launching several new offers.

Citi PremierPass®

• 10,000 bonus points after $300 in purchases made within 3 months of account opening
• 0% APR on Balance Transfer for up to 12 months
• Purchase APR as low as 11.99%

Citi PremierPass® Elite Level

• 20,000 bonus points after $600 in purchases made within 3 months of account opening
• Purchase APR as low as 13.99%

The “bonus points” awarded for using the above cards can be redeemed for flights on any airline with no blackout dates, discounts on hotel stays, retail gift cards, electronics, and even credits through Citi’s ThankYou Network.

Citi® Platinum Select® / AAdvantage® World MasterCard®

• 25,000 AAdvantage® bonus miles after you make $750 in purchases within 4 months

Citi® Gold / AAdvantage® World MasterCard®

• 15,000 AAdvantage® bonus miles after you make $750 in purchases within 4 months

The AAdvantage® bonus miles awarded for using the two above cards must be redeemed through American Airlines’ frequent flyer program for airline tickets, hotel reservations, or rental car reservations, as well as a few other options.

Now is most likely the best time for finding great deals on holiday items like Christmas tree ornaments and decorations. While I’m inclined to say that holiday tchotchkes are generally overpriced to begin with, I’ve spotted discounts up to 75% off of the regular price over the past few days. Most people, particularly those who plan and prepare for the holidays, are just happy the year has ended. They’re not thinking about preparing for next Christmas or Hanukkah.

Meanwhile, the stores need to unload their unsold holiday inventory. It’s time to start making room for Valentine’s Day junk. Use this knowledge to take advantage of the strong supply to demand ratio. If you have the storage space and can’t reuse what you already have, consider buying what you’ll need next December now at a deep discount.

Updated November 30, 2008. Any indented text is excerpted directly from the issuer’s marketing.

Here is an update to an article I posted about four months ago. If you’re looking for 0% APR offers, here are 79 of them.

Warning! Taking advantage of credit card companies may be fun and profitable, but it is dangerous if you don’t know what you’re doing, or if you do know what you’re doing but are not careful. If you miss one payment, in most cases, you will owe back interest at the default rate.

That being said, here are a bunch of credit cards offering 0% APR on purchases, balance transfers, or cash advances for a year or six months. Use these cards responsibly, and you can save yourself money two ways. First, you can earn interest on your cash while paying off the card, and second, you can use inflation to your advantage. For example, if you pay $100 each month for thirteen months, your last payment is worth about 3% less in purchasing power. Here are 79 cards that offer 0% interest on purchases or more.

Note: Since posting this list on November 27, 2007, many issued have canceled these offers. The list below reflects what is currently available of the original 79 offers.

Discover Business Miles Card (apply here)
0% APR on purchases for 12 months
13.99% APR on purchases (standard)

You don’t have to have a business to apply and be accepted for this card, as with any business card. With this card, you also earn miles which can be redeemed for travel credits. The standard Discover Business Card offers a similar introductory rate, but rather than miles, earns the spender 5% cash back on office supplies, 2% on gas, and 1% on all other purchases.

Here are more 0% interest introductory offers on purchases, balance transfers and cash advances.

Discover More Card: 0% APR on purchases and balance transfers for 6 months
Discover More Card – Sealife Collection: 0% APR on purchases and balance transfers for 6 months
Miles by Discover Card: 0% APR on purchases and balance transfers for 6 months
Discover More Card – American Flag: 0% APR on purchases and balance transfers for 6 months
Discover More Card – Wildlife Collection: 0% APR on purchases and balance transfers for 6 months

Discover More Card – Monogram: 0% APR on purchases and balance transfers for 6 months
Discover Open Road Card: 0% APR on purchases and balance transfers for 6 months
Discover More Card – Clear: 0% APR on purchases and balance transfers for 6 months
Discover Motiva Card: 0% APR on purchases for 12 months
Advanta Platinum BusinessCard: 0% APR on purchases on balance transfers for 12 months

Advanta Platinum BusinessCard With Rewards: 0% APR on purchases on balance transfers for 15 months
Discover Open Road Card for Students: 0% APR on purchases for 6 months
Discover Student Card: 0% APR on purchases for 6 months
Discover Student Card – Tropical Beach: 0% APR on purchases for 6 months
Discover Student Card – Clear: 0% APR on purchases for 6 months

Discover Student Card – Monogram Collection: 0% APR on purchases for 6 months
Blue Sky from American Express: 0% APR on purchases for 6 months
Clear from American Express: 0% APR on purchases for 12 months

Blue from American Express: 0% APR on purchases for up to 15 months
Blue Cash from American Express: 0% APR on purchases for 6 months

Citi Bronze AAdvantage® Card for College Students: 0% APR on balance transfers for 6 months

Citi Driver’s Edge Card for College Students: 0% APR on purchases, balance transfers, and cash advances for 6 months
Citi Dividend Platinum Select for Students: 0% APR on purchases, balance transfers, and cash advances for 6 months
Citi mtvU Platinum Select Visa Card for College Students: 0% APR on purchases, balance transfers, and cash advances for 6 months

Citi CashReturns MasterCard: 0% APR on balance transfers for up to 12 months
Citi Diamond Preferred Card: 0% APR on balance transfers for up to 12 months
Pulaski Bank Gold Visa Card: 0% APR on balance transfers for 6 months
Pulaski Bank Visa/MasterCard: 0% APR on balance transfers for 6 months

Capital One® No Hassle Cash^SM Rewards – Good Credit: 0% APR on purchases until October 2009
Capital One® No Hassle Miles^SM Rewards – Good Credit: 0% APR on purchases until October 2009