Life Hacker makes a good case for buying a smart phone if you have been on the fence. at the very least he explains how to take advantage of possible savings if you already own one.
10. Find Fee-Free ATMs
9. Always Have Your Coupons
8.Use an App to Compare Prices When Shopping
7. Keep Digital Copies of Discount Cards
6. Actually Use Your Phone to Save Money
5. Save Money on Groceries
4. Get Cheap Gas
3. Make Calls Using VOIP
2. Don't Pay for Text Messages
1. Tether at Little to No Cost
To see how all this makes sense click here for the full picture.