Overnightprints.com and zazzle.com (and DA's print shop too!) make folded greeting cards. In fact, I used to buy from my own DA print shop all the time until I was able to afford to buy more in bulk from other places. Before I bought a printer to make my own prints, I used iprintfromhome.com for my 8x10's Should you happen to join, feel free to use my name 'Angela Sasser' as a referrer and it'll net us both some print credits.
I still use them when I buy in bulk as well. They're an excellent service! Best of luck!