How many tokens can you get for $1?

I believe its 4 for a dollar, and more for spending more (25 for $5, etc) but don't quote me on that.

4 tokens for $1.00 125 tokens for $20.00

Ben has it exactly right $1 for 4 tokens but with increasing bonus tokens for doing more at once. A $20 bill in the token machine nets you 125 tokens.