Don't buy on credit
You'll be much better off if you buy things with money you already have. There are several companies that people commonly shop at like Dillards, JC Penny, and Victoria's Secret that make more money from people buying things on credit than they do from selling merchandise. Most stores have a policy that the cashier must ask you if you want to have a store credit card when you checkout. Victoria's Secret won't let their employees work unless they sell a certain number of cards, leading to aggressive tactics on the employees' part. JC Penny goes a step further with their credit card. If you buy something with their card and don't pay it off, they can try to collect from you even if you go bankrupt. And their collections agency, GE Money Bank, is quite aggressive. Aggressive collections tactics aren't illegal, but they should be.
Don't go into debt and be careful.
This link is from mint.com, a free budgeting website. It covers bad deals that many companies pull legally that you shouldn't be caught in.
Dr. Scott Marsh, a finance professor at BYU, has created a website that has all kinds of good financial resources for the layperson. He has created a list of books that are ranked by the quality of their advice, from good to bad. For trustworthy advice, try reading a few of the books and looking around the rest of the website.

