1. Read customer testimonials before you buy anything. People are more than pleased to complain about bad service online, so search for sites and testimonials which are terrible so you know what you're getting into. You should take bad reviews having a grain of salt, but if you see many, you know there is a problem.
2. Sign up for your favorite online stores' newsletters. Often online stores will send out daily, weekly or monthly newsletters with special sales, discounts and deals. If you like to save money, you could possibly score some great deals on items you were going to purchase anyway.
3. Check out coupon sites. Anything you want to buy may have coupons or discount codes. Before you buy something, ensure that you have the ability to take a few seconds and do a quick search. You could even want to bookmark some coupon sites to have ready when you buy.
4. If you're considering buying a product online, browse the reviews. The reviews from other people that have used the product should be able to give you a good idea about the product. You could possibly find out the quality of the product, when it worked as described, and if you should make the purchase.
5. If you're making an online purchase, don't hesitate to contact customer service if you have an issue. By contacting customer service before you make your order, you'll learn how helpful customer care is and how quickly they respond. This is useful information to have in case something goes wrong after you've made your purchase.