The credits system is a good way to go, because you can get people to spend more when it doesn't feel like real money (a la Microsoft Points). Amazon Payments

The credits system is a good way to go, because you can get people to spend more when it doesn't feel like real money (a la Microsoft Points). Amazon Payments provides an easy way to do it too: https://payments.amazon.com/sdui/sdui/business?sn=devfps/aggregated https://payments.amazon.com/sdui/sdui/business?sn=devfps/agg...