Since several people have asked... I really mean it, pay what you can if $20 is too much.
A few people have commented on the price. I decided on $20 because that's something like what a play costs. And, even though many volunteers have helped me and are helping me (for which I am very grateful), I have also spent lots of money on this project and have not been able to pay myself back. I also haven't really worked since April and will not be eligible for maternity benefits. I'm not doing this to make money but if it happens, it would be helpful.
At the same time, I don't want to turn anyone away. So there you go: $20 or pay what you can.