Recently the game braid was released for ubuntu in the ubuntu software center. however, it seems they don't take payments from paypal yet. Is there a political reason for this, or a technical one?
PayPal is now supported in Software Center:
click the buy button in software center...
login to your launchpad account when prompted... and then you can pay using PayPal
Generally, there are a lot of payment types we could support (ie mobile phones payments or geographical specific ones) but each one needs a lot of work to integrate. With the constraints are fraud recognition, tax and technical integration our main objective is to have the most popular and widely used methods.
Paypal is very popular and we've been asked about it by quite a few users so it's an obvious one to add. It's just a question of priority and resourcing!