I recommend a 16 GB unless you find a 32 GB on sale.
When it comes to price vs memory, the 32gb is the cheapest, even at full price. I got my 32 for a massive 115$ (including both federal and provincial taxes) and don't regret one bit. (Bought at least 10 digital games since i got mine, + the 20+ games i had on my PSP GO. --- Married to Clay, Driftveil city's gym leader Official Roserade of the Pokemon X/Y boards
while the 32gb is ideal, you'd be a serious moron to pay the $80-100 price tag. Don't get a 32gb if you can't find one for under $50. It's not worth it trust me. --- PM me for the $20 referral code if you're interested.