>>2942760
You can print cards at an office depot or Kinko's or whatever, at 300dpi or higher, on glossy, heavy cardstock. Arrange as many card faces as you can fit (shoot for 2.5x3.5 inch cards), and remember you need space between them. I think I got six or eight comfortably on a page when I did it.
When you design the card backs, you'll need an extra probably half-inch bleed because the folks at Kinko's will absolutely need you to explain to them twice that you want to print on the back of the cardstock, and they will have trouble lining the stock up perfectly. Make sure they print the faces on the good side and the backs on the dull side. They should let you inspect their stock before you print, especially if you're printing a lot.
I recommend a sliding cutter over a guillotine lever style one, because you will fuck up if you get complacent. The scrapbooking section of a hobby store has hand dies for rounding the corners of cards off. It's labor intensive but it's almost worth it.
If you want to do this more than a few times, forget everything else I said and go through a place like The Game Crafter.