I was browsing on eBay and I found a big selection of cheap classical CDs from a store called Hoots Loot Quality Software. No idea of the quality, but it would be hard to go wrong at $1.99 each. I picked up some Grieg, Hayden and Mozart to fill in some gaps in my collection.
To find these bargains, search on hoots and famous. If you visit their store link and search on the same (title only), they have about 250 additional selections that you can "buy-it-now".
Happy hunting.

