Snapfish! I've used them the past two years and they've been great. Through 12/2 you can use the code JINGLE and get 55% off, or if you can order before 11/30 you can get 60% off with the code CARDSFB.
If you miss those, they do deals every couple days so just keep checking back. You do have to have them shipped though to get the deal. My parents saved more than $50 on their cards this year.