Up to a hundred and twenty damn dollars, according to GameStop. The retailer has posted listings for four sizes of Vita memory card, including a 4GB card for $29.99. 8GB for $44.99, 16GB for $69.99, and 32GB for the aforementioned $119.99.
That's perfectly in line with the Japanese pricing for the memory cards -- and it's also a strong argument in favor of getting a small card for save data and just buying all your games retail, like you did on the PlayStation 1. Welcome to the future!
Update: Sony told IGN that the 4GB cards would actually retail for $24.99 and the 8GB cards for $39.99. However, GameStop has yet to change its prices. Either GameStop had the wrong MSRP, or it had the right MSRP and added a premium -- or Sony saw the response to its suggested memory card pricing and corrected it a bit in our favor.