I won an auction for a Motorola Q on eBay and have had nothing but problems since.  Forturnately, the seller was stand-up and honest and took back the phone for a full refund, but just be cautious because you may not be as lucky.  My Q phone arrived and was defective (the phone would not charge properly and hold the charge.)  The phone was listed "as new" and in perfect condition, and it certainly looked new and came in the box with all of the accessories. However after a day with it, I found that the phone was defective. 

I took the phone to 3 different Verizon stores to figure out the problem, and they said there was a defect in the battery compartment.  Unfortunately, according to Verizon, as soon as the product changes hands . . . even if BRAND NEW in a box, the warranty voids and you cannot exchange or get any help for the product.  The only way the warranty is valid is when you buy it, Verizon records you as the original purchaser (the Verizon reps said that they record who each one is sold to. . .unless an authorized seller, and then the authorized seller records the original purchaser.)

So what's the lesson?  You may save $100 on a new Q on an auction. . .but you may be paying much more if it's defective and the seller is not on the up-and-up like mine was.