I would have bought it, yet the Amazon checkout refuses to let me pay using my Amazon gift card balance. It seems to want me to buy via credit card. If there

I would have bought it, yet the Amazon checkout refuses to let me pay using my Amazon gift card balance. It seems to want me to buy via credit card. If there is a way to buy it using my gift card balance I don't see it. Ah well, and I was willing to give the developers $20 or so.