I don't buy used electronics. There doesn't seem to be a lot of great deals on ebay anymore. Occasionally, I'll see something, but for a few more bucks the same item can be purchased brand new. Besides, there are some great lesser known brand electronics (Speed Passion, Hobbywing, do I dare say Turnigy???) that are a fraction of the price of well established brands and are essentially the same item with minimal differences unnoticeable to the average racer.

Be cautious buying the Chinese stuff (Turnigy, Hobby King, etc). You get what you pay for! If you're serious about racing, buy the quality stuff from the start. Otherwise you'll spend more money replacing everything like I did. I've since replaced everything in my cars and the difference to me is night and day.