Hey there!
There are tons of places to get two ways! First you have to figure out what kind you want - do your research here on the boards - you'll find the most common recommended brands are Cobra and Motorola. I have two different kinds of Motorolas myself - older ones that are pretty basic, and fancy new ones (T6300). A friend of mine just got the T6220's and she loves them. We'll be testing them in Disney this week!
My only caution with getting two ways off ebay (trust me - I am have made a few purchases off their myself) is if there is a rebate offered, the sales receipt must come from an actual physical store (don't ask me how they know, but it's a requirement). AND - there are some great rebates being offered for Motorola's right now (
www.motorola.com/talkabout).
I just did all the legwork on this - so it is fresh.
Best Buy and Circuit City have pretty good prices - and a place to return them too, should something happen - but not a great selection. You can also find them at Office Depot, Office Max, etc. As far as online - just make sure you can get a physical store receipt - I saw some on half.com, 800.com and
www.getbuzy.com. The ones that I just bought, I got at Service Merchandise - which is going out of business, so I got a dandy deal, and a $25 rebate on EACH one.
I hope that helps!!!