Holy cow!! Encoders are much more expensive than I ever expected. The cheapest encoders I can buy are about $90 each from Automation Direct, and I need two. Need to find a cheaper way to do it.
After extensive searching and calling a few companies for prices, I found another encoder solution. Digikey has CUI modular encoders that attach to an existing shaft for $30. They look kind of cheap, but they would probably work fine for this project. I would have to figure out how to mount a shaft for them to attach to, though. The $30 encoders are capacitive, however that works. They also have some that are standard optical encoders for about $37. When cost is a major factor, these look pretty good.