They'll all do a 30 day trial, but only for NEW customers. So if you are a VZW customer, try going to a Sprint store. You'll need to go through the usual credit stuff, but should be able to walk out with a card.

You could also contact www.rovair.com and rent one but the in-store thing might be quicker if it's that important.

Another option is seeing what the full retail price is of a card and getting a new one in the Verizon store and having it programmed for your account. It will cost a bit, but you should be able to return it (I think) with nothing more than restocking fee.