Advantages and Disadvantages to online shopping:
Advantages		Disadvantages
make transactions at any hour convenient delivery (direct to doorstep even) purchase items not available locally avoid local sales taxes bargain prices		must wait for delivery shipping costs customer service may be poor or not exist cannot handle the actual product before purchasing reliability of sellers may not be verifiable potential of being cheated is greater

Advice for shopping online:

• Know the e-tailer. You can check with the Better Business Bureau or a local consumer protection agency for complaints. It's nice when a site is “certified” by agencies such as WebTrust or The Public Eye to prove their trustworthiness. Beware if they don't willingly offer information regarding their physical location and phone number. Also be leery of a site which doesn't have their own domain name; if they are using a free hosting service like Geocities or Angelfire.
• Be sure the e-tailer has an acceptable customer satisfaction policy. An online company should be willing to offer concrete commitments to stand by their products and service.
• Don't be afraid to call the e-tailer directly and make certain you can get a good sense of their ethics.
• Purchase in a secure environment.
• Use a payment method that limits liability. All credit cards have a $50 limit, by law, but some may guarantee $0 liability. Another advantage to using a credit card is the ability to reverse the charge if dissatisfied with a product.
• Be sure to keep a printed record of all transactions.
• Keep all personal information private. Don't share address, phone or Social Security numbers with parties you do not trust.
• Laws that protect phone purchases also apply to cybershopping.
• Take a little time to do some comparison shopping. Search the internet for other sites that sell the item you want to buy and see if you can find a better price or more reliable/reputable source.
• Be sure to check all associated costs, including shipping and handling.
•  Be clear on any guarantees or warranties. Know when to expect delivery.

Finding what you want:

• Search Engine Tips

Purchase Disputes: 

• Buyer Beware. Consider carefully before purchasing.
• Contact Internet Consumer Assistance Bureau. 

Yahoo's advice on safely shopping online
“Shop Safely,” from the Federal Trade Commission
Better Business Bureau advice
SafeShopping.org
Credit-Land.com
CNET “Safe Shopping Online”
BBB points out “Shopping Safely Online”