Just to expand this answer slightly for people coming across this thread via google. From the docs
Stripe accounts in the US and Europe support a number of
currencies. To create a charge in any of these currencies, you need to provide the amount in the smallest common currency unit. For most, this is the amount in cents (or pence, or similarly named unit). For example, to create a charge for €1.00, you would set
amount=100(100 cents).
For zero-decimal currencies, we use the regular denomination. For example, to charge ¥1, you should setamount=1 (1 JPY), since ¥1 is the smallest currency unit.
So in the dashboard when you set a plan to $399.00 it automatically makes the proper API call of 39900. The Dashboard does some UI prettiness where it displays dollars and cents instead of just cents.
Matt