1. When you are searching for a spot to buy an item and no results are most often from familiar retailers, you should be hesitant about entering your details. Look for security signs from Verisign or Cybertrust, so that you know the retailer is not out to take your hard earned money.
2. Read customer testimonials before you buy anything. People are more than pleased to complain about bad service online, so look for sites and testimonials that are terrible so you are aware what you're getting into. You need to take bad reviews having a grain of salt, but if you see many, you know there is a problem.
3. Make sure that you're entering your payment details on a good site. Try to find "https://" within the URL from the site that you're attempting to buy something from. If you don't see that or no sign of any website security, then it's probably a good idea not to trust those people with your account information.
4. Do not forget to comparison shop when you are looking for things online. People usually accomplish this when shopping in physical stores, but they don't think about it on the Internet. If you go for the first sale you see, you will find a chance you may miss out on a better deal somewhere else.
5. Sign up for your chosen online stores' newsletters. Often times online stores will send out daily, weekly or monthly newsletters with special sales, discounts and deals. If you like to spend less, you might be able to score some good deals on items you were going to purchase anyway.