1. Make sure that you're entering your payment details on a safe and secure site. Search for "https://" in the URL in the site that you're trying to buy something from. If you don't see that or no sign of any website security, then it's probably a great idea not to trust those people along with your account information.
2. After you have found the items you would like, check to see if there are any coupons offered. There are many websites that offer coupons. These coupons can be a certain percent off, a certain dollar amount off or free shipping. Many times several coupons are offered. If this is the situation, choose the one that will save you the most money.
3. Read customer testimonials before you buy anything. People are more than happy to complain about bad service online, so look for sites and testimonials which are terrible so that you know what you're getting into. You need to take bad reviews using a grain of salt, but if you see many, you know you will find a problem.
4. If you're purchasing clothes or shoes online, be careful with the sizing. Some items typically run smaller or larger than normal. Some shopping sites will advertise if an item runs true to size. If the site doesn't list anything about sizing, glance at the reviews. In most cases, if an item is running larger or smaller, the reviewers will let you know.
5. If you find an excellent product on your favorite site, search for it in an internet search engine before you buy it. Make note of the model number or brand, and do a quick search to make sure you can't obtain it cheaper from somewhere else. You might be able to save a few dollars that way.