I ordered my boards through seeedstudio, because I had a pretty good coupon from a previous project. But ALLPCB will send you 20 boards for $56 which is still a bit cheaper than what I spent for mine. As far as chips, I spent $34.99 for a pair of 64MB modules on eBay, which had enough chips to make 9 completed SIMMs. All in all, a bit shy of $7 per SIMM. Not too shabby! I have two IIfxs to populate, and will need a couple more 64MB modules to complete the set, which will leave me with 2 spare SIMMs and 2 bare boards in case of a failure. So far, I've only built up the 4 shown, but they pass all memory tests I've tried.
I do feel bad for pillaging the chips from working modules. If I were to make a lot of these, I would certainly try to find a supplier of bare chips.