Don't forget Ebay..
You can get a AT328 with Arduino bootloader for $5 shipped (china), and even the Anarduino (minimalist Arduino w/ICSP, no USB) for about $10 shipped (USA I think).... As for the rest, like the attiny, just search Ebay for 'em, they end up being in the Industrial Supplies "section".
As always, if you order from China or Tiawan, be prepared to wait a shile for shipping... like weeks...