I recently got the Echo 108 freewheel for $60 on ebay. It's a nice freewheel, although I was initially surprised at the amount of side to side play in it. From what I've read on some trials boards, the play is pretty normal and I haven't had any issues with it. I figure if the trials guy use 'em, I'll be fine for around the neighborhood.

I've also had a Dicta and an ACS Crossfire. The ACS is decent for under $20, chromoly construction, 30 POE.