This is a super easy deal to run. If you order 50 full color business cards at Overnight Prints (one or two sided) and use the coupon code REDDIT then you will get them for $1 shipped.
I already did this deal and it works great! If you shop through Ebates you might get an extra 10% back (making the cards only $0.90) although the rebate might not work with an outside coupon code (worth a shot though!).
UPDATE – this deal is dead as of noon today. The coupon code is now taking 20% off (instead of 10%) and charging shipping.
This deal is good through March 31st. Thanks to Kim from Shopping Bookmarks for emailing me this deal.