Plugin for storing customer payment information

Hello,

I am trying to figure out if there is a plugin that can enable the following process:

1. User comes to site
2. User is asked to/allowed to enter in their payment information
3. Information is validated and stored for later use (user is not billed at that point)
4. At a future point in time, I can bill that customer for service rendered/product shipped using the stored payment information.

This is similar to subscription billing, but the difference is that it is at irregular intervals and for varying amounts.

I am very new to WP and any help is appreciated.

Thanks