[...] I was hoping to find a source that was a little more reasonably priced.
Most businesses that produce PCB's as part of their daily routines, dumps nice pieces of FR4 (fibre glass) board from time to time, in chunks larger than any board that you're likely to use - single sided as well as double sided. And while it won't help you with through hole plated jobs (nothing will, as they're drilled before the copper is plated on), wire goes a long way connecting layers.
A small box of chocolate and/or a smile delivered to the right person, may net you enough PCB material to last you the next decade or so.
Check the Yellow Pages for local electronics producers.