Bango has an API for getting their TOS. We should be prompting users to agree to Bango's TOS before they set up their account. Store the timestamp that they agreed to the TOS - in the future we'll need to get them to re-agree periodically.
cvan: if you didn't start this yet, you can toss it back to me.
on adding a new payment method, we prompt the developer to accept ToS.