Best for: The big-time bargain hunter who wants to see all the options.
How it works: This free iPhone app aggregates local and nationwide restaurant discounts from around the Web (think daily-deal sites, like Groupon and LivingSocial, plus blogs, Facebook, and Twitter). Some offers must be purchased in advance, which you can do through the app. Use it to make dinner reservations, too.
Downside: The app is available only for the iPhone. The website provides information about the app, not the deal database itself.
Average discount: 50%
Where it works: Nationwide.