Before you spend too much money, don't forget to check out the many sharity sites for downloads. You can find collections, oddities, etc.
Great place to start.
Here's a nice list from a 2010 recap from Ernie Not Bert
Falalalala.com is great too, but down at this time.
Another good source, at least for links is http://bongobells.blogspot.com/
. I don't know that it is an active blog any longer, but there are tons of links to music on the left side of the page.
I've alreay found some I don't have, but must!!