Most people only do it on major purchases like appliances, furniture, or electronics because it’s time consuming and requires a fair amount of forethought.
Groupon is a service that offers 50% discounts on a regular basis to restaurants or entertainment spots in your area. LivingSocial has discounts to local social events and vacation spots.
If you subscribe to their news feeds or fan pages they’ll often notify you about all the best sales, discounts, and special events ahead of time. This is a great way to buy smart and stay within budget.