The others listed here are real busy sites, lots of words, and NO pricing.
You overgeneralize. iteadstudio has all their prices listed.
10 boards, 50mm x 50mm, (just under 2inch x 2inch), $9.90. So nearly 40 total sq inch of board for $9.90, or ~25 cents/square inch.
10 boards, 50mm x 100mm, $14.90, ~19 cents/square inch
10 boards, 100mm x 100mm, $19.90, ~12 cents/square inch Can fit a ton of parts on 100mmx 100mm board.
Slow cheap shipping, or DHL for faster shipping. Chinese Holiday ends in3 days.
I've not had much calling for 25mmx 25mm boards; my most recent custom design used a '328P TQFP and couple components on a 50mmx 50mm board as a controller for a lot more parts on 2 50mmx 100mm cards. (size restrictions determined by housings the cards go into).
25 x 25 doesn't allow much room for connecters. My 328 Mini and 1284 Mini cards are larger then 25 x 25, mostly due to room for 0.1" connectors.
Smaller than that and you're not making much than a SMD to DIP breakout board I suspect, or something really custom.
http://www.crossroadsfencing.com/BobuinoRev17/
