WOW. You got in on that deal? Online purchase, right?
You have 2 options when going wireless:
1. Standard 360 USB Wireless Adapter. I'm sure you've seen this for $100.
2. Xbox 1 Wireless-G Adapter. This runs $40 at Frys.
http://shop2.frys.com/product/5478789
The Xbox 1 adapter has quite a few pros:
+ This utilizes the cat-5 jack on the back of the system, so it'll keep the rear USB free.
+ It's AC powered, so it doesn't leech from the console.
+ it's $60 less than than option 1.
+ If you have an Xbox 1, you can dual purpose the device.
If you ever wanted to trade, I have a brand new, white, 65nm Premium console here. It's absolutely untouched with wireless controller, 20GB HDD, Marvel Ultimate / Forza 2 game. I'll even throw in a few games too.
h: