Is this an additional charge or do you get it when u buy an AP??
As AKV707 said, it's $75 for one card. ($50 for an additional card - and don't lose your card or you'll have to pay $50 to replace it!)
That said, I think it's still an awesome deal and can't imagine not using it. We do a lot of signature dining and it's great to get the flat 20% off including off drinks if we want them.
As for APs vs MYW non-exp, I like the flexibility of just being able to go in a park for a meal or just to do one thing without "wasting" a day.