The new costs are
That is the total for the maximum of 20 buys! Your VIP Level will dictate how many buys you are entitled to.
I'm sure most already know this, however, to see your entitlement, click to purchase stamina and you will see....
Buys left / Buys allowed (I.E 10/10 indicating 10 purchases left for today from a total of 10 allowed by your VIP Level)
Hope that helps!
Edit: Clarification (Hopefully!)