Hi Wendy-
Betty posted in another thread asking about winkflash- they do have 4x8's and they are 35 cents including the envelopes. I'm going to try them this year!
http://www.winkflash.com/content/photocard.asp
NEVER MIND
THEY DO HAVE BORDERS- YOU CANNOT HAVE YOUR PHOTO ON THE WHOLE CARD
Sorry- I'll keep looking!