I'm coming very late to this topic, sorry... but since I don't see anyone else having mentioned this, I wanted to chime in. The blues dance I now run in Seattle uses Square to track attendance and cash. It's simple to set up and our door volunteers seem happy with it. We charge a sliding scale and just have separate "items" for each dollar amount. When we used to have "regular" and "student" prices we had buttons for those as well, and a custom price item for donations. Square automatically tracks the number of each item sold, and the times.
On a tablet (we use an iPad, and I would assume it works on an Android tablet as well), Square also does cash drawer tracking -- enter your starting cash, track transactions, and enter your final counts; it'll tell you whether you're off and by how much. It does not allow for cash drawer tracking through the phone app, though. I'm not sure why not, or whether they're going to add it eventually.
And of course, Square allows us to take credit cards too, which has pros and cons but overall I'm very much in favor of it.
Koren