The official Groupon app is available exclusively for Nokia Lumia phones. It scans your current location and presents you with daily deals and/or getaway deals, and you can get the deals directly from your phone, so you never have to print a coupon again.
The Groupon app is expertly made, it brings almost everything the desktop version has to offer making the app truly mobile and handy, there is augmented reality integrated into it to see deals close to you, and there is even Nokia Maps integration to go get that deal you want! You also have the option to share with friend via email or on facebook or twitter. there isn't any fault I find with this app, perfect score!
Groupon is supported in over 700 cities, so chances are it's in your city.
Get the Groupon app from the marketplace and try it out, oh and it's FREE!