I have no affiliation with this site... but it looks like a good place to get in on a shared PCB order.
I plan on using them in the future.
Here is a quote from their web site...
http://dorkbotpdx.org/wiki/pcb_orderQuote:
"It's $5 per square inch for three copies of your two layer design. So, a 2 square inch design would cost $10, and you'll get three copies of your board. Shipping within the US is included, and there are no setup fees."
