I just got something like 2000 on ebay for $35 bucks. Best deal. Except 8 batches later and I'm switch to kegs. I'd be glad to sell the majority of the remainder to you.
My LHBS sells them in one pound bags (IIRC about 160 caps) $3.99 for plain (or colored) crowns or $2.99 for miscellaneous overruns (strawberry soda, cola). But since I started kegging I don't need too many any more.
i get my caps from either LHBS, Midwestsupplies, Austin Homebrew, or Williams brewing. all depends on who I am making my current order with, and i just add them on.
I don't use many now, I keg most of my beer, and have a couple cases of swing-tops now.