I need around 100 thank you cards (generic or birthday themed). In local stores they are sold in packs of 10 for like $4, and that's a lot to spend on them.

Does anyone know of an online source for bulk thank you cards at reasonable prices??? Thanks!

Any site that offers things like invitations also has Thank Yous available... or you could hit the office supply store for some bulk card stock and print them yourself.
Or you could get some pretty stationary and just write old fashioned, proper "thank you notes"... much more personal and much less costly.

You can probably find them at Party City, or Michaels or Jo-Ann or even Wal-Mart or Target. But then you have to pay for shipping. Check them out on-line and then visit the store if there is one in your area. I believe I got mine at Michaels and at Factory Card Outlet.