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.
Howit works: Sign up with this app (available for Android and iPhone and as a website) to receive twice-weekly e-mails touting a deal (30 percent off your bill, free wine with dinner) from trendy restaurants. You have 24 hours to claim each offer's pass code, which you then show to your server.
Downside: Procrastinators, beware: Most pass codes expire within a few months.
Average discount: 30%
Where it works: Chicago, Los Angeles, New York City, and San Francisco.
Best for: Plan-ahead types in search of upscale meals.
How it works: Enter the number of your party and the time you want to eat and this app (available for Android and iPhone and as a website) will present a list of mostly high-end restaurants with available tables, along with discount offers. Make a reservation from the site or the app, then show your server the electronic voucher when you sit down.
Downside: Discounts tend to be smaller during prime reservation times. (You may get a 30 percent break at 6 P.M. on a Tuesday, but only 20 percent at 7 P.M. on a Friday.)
Average discount: 30%
Where it works: Atlanta, Boston, Chicago, Denver, Los Angeles, Miami, New York City, Philadelphia, San Francisco, and Washington, D.C.
Best for: When you're out and about and want to eat now.
How it works: Available for Android and iPhone, this app displays nearby restaurants offering immediate discounts (starting at 50 percent off). Show your phone's Scoutmob screen to your server to get the lower price.
Downside: You have to be willing to try an unknown place. The app focuses on restaurants that need business, not spots with buzz.
Average discount: 50%
Where it works: Thirteen cities, including Atlanta, Boston, Dallas, Los Angeles, New York, San Francisco, and Washington, D.C.