Honest-merchant27 via eBay offers this Folding Credit Card-Shaped Multipurpose Knife in Black for $1.20 with free shipping. That's tied with last week's mention as the lowest total price we've seen for a credit-card-shaped folding knife. (It's also a current price low by $6.) It features a stainless steel surgical blade and built-in protective sheath.
This item may take up to eight weeks to arrive.