Buying an iPhone (or any smartphone) isn't easy if you consider yourself a frugal person. I struggled with my purchase of the Android G1 because, deep down, I knew I didn't need to buy it.

I just really wanted it.

For all you other frugaholics that need a little push to come over to the dark side, here are six ways an iPhone (or most smartphones) can save you money:

ATM Fees

Ever had that sinking sensation of despair when you absolutely need to take cash out of another bank's ATM machine? I have used the maps feature on my G1 to find an ATM nearby at least three times in the last month. At that rate, I'll save around $70/year by never spending those pesky $2 to get access to my own money.

Music

Love listening to music but don't want to spend a whole lot of money downloading songs or (if you're really old school) buying CDs? Say hello to Pandora—one of several apps out there that stream music to your phone for free. Not only that, it learns which songs you like and which ones you don't, exposing you to music you may never have heard of before. An added bonus! I've also used Imeem and it works just as well.

Price Checking

Say you're at the store and you see a book or DVD you really want to buy. In the olden days, you had to fight the urge to buy it and try to make it out of the store before succumbing to the temptation. Now you can whip out your phone and check to see if a competitor has a lower price. Knowing you can get a better deal should make it easier to walk out of the store without buying anything. And if you have a G1, check out the ShopSavvy app—it actually lets you scan the barcodes of thousands of products to do a price check. It'll even tell you the prices of real stores near your current location—pretty cool!

Cheap Gas

Remember how crazy people became last year when gas prices were so high? Some were even driving the long way home to get a better deal on gas. Well, if you want to keep saving on gas regardless of what happens to the price of gas, check out Gas Buddy. It's a comparison tool that will show you where the cheapest gas prices are in your neck of the woods. Just please don't drive an extra 10 miles for a "deal."

Books

I love reading, but buying book after book adds up pretty quickly. And when there are thousands of great, free books out there you haven't read, why spend any more money than you have to? There are a bunch of e-readers out there that allow smartphone owners to read books on the go. Check out Stanza or one of the many other apps out there for smartphones. Even better, check out all the books that Google has made public by accessing their mobile site on your phone.

Phone Calls

You remember Skype, right? Wait a minute, isn't Skype the program people use at home to call other computers with Skype for free? You got it, and now you can get that functionality on your phone. There's a Skype app for the iPhone and there's one called iSkoot that taps into your Skype account for Android phones. As long as you have Wi-Fi access, you can call anyone else with a Skype account for free or any phone in the world at a really cheap rate.

If you're still not convinced, check out the different ways a smartphone can save you time—if you're saving time and money then you know there's nothing to lose.

If there is an app out there that has saved you money, feel free to share your story so we can compile a "master list" of ways to save money!