You can try ebay if you trust it as a place for buying park tickets...
Another option...this might sound strange...but the more days you buy on a single ticket, the cheaper the individual tickets become. The first time we went in May 05, we bought 10 day tickets with no expiration. The cost per day drops from nearly $70 to almost $30/day if you buy them in "bulk" like that.
Also, you're locking them in at today's rates, since the no expiration option means they're good for life.
In our case, in May 05, we had no idea when we would coming back, but we figured our kids were 6 & 3 at the time, so figured sometime before they're 18...lol. Little did we know we would have the best vacation of our lives and want to come back just a year later, and then buy a home there!
Now we're on the 2nd half of our 2nd 10 day pass with no expiration in 2 years! LOL
We might consider buying APs next, but the no expiration thing means if we aren't there within a calendar year then we can always go back whenever we like and reuse them.
There are some online discount ticket stores, like these guys:
http://www.officialticketcenter.com/
But it's not much less expensive than buying them in the parks...Disney doesn't discount their tickets very much. It IS more convenient though to have them in advance of getting there so you're not waiting in what can be long (and hot) lines.
