Please, DO NOT buy tickets from Ebay.
There is no way to verify (1) that the tickets are legit and not good forgeries, (2) that the tickets have not been used (the bio-system they use won't allow other users to use old tickets), or (3) that there are any days left on the tickets UNTIL you are at WDW.
I've been a member here on the DIS for several years and have read more than one sad post about someone getting taken for hundreds of dollars when they bought tix on Ebay.
There are legit discount ticket sellers including
http://www.ticketmania.com and
http://www.undercovertourist.com.