There are a number of web sites that are designed to find deals. I hate popups and affiliate sites. These are the core sites that I use:

General

• Craig's List
• Slickdeals
• Woot (careful, the site's a gamble)
• Freeafterrebate
• What's Shakin' @ Buy.com
  

Electronics

• Techbargains
• Car Stereos
• Home Theater
• Philips Electronics
• Ben's Bargains

For anything else you need to hit local stores. Look at flyers. If you're in the Boston area, try Amesbury Chair for inexpensive wood furniture. For stuffed couches, if you want quality construction and a good value, I recommend King Hickory.