Suggestion:
If you find it used it may be cheaper. Try eBay. If you want to use wires you can set your 360 up by a computer with wifi (laptop or desktop) and bridge the internet connection so you can connect the ethernet wire from your computer to your 360.
Heres the website for more instruction
http://www.youtube.com/watch?v=XBT-B-mfkBk&playnext_from=TL&videos=fF06BBlMeJU
