Also, the payment is currently really low, less than $0.2 per each poll over free quota. So I don't think cost would ever be a problem
Even if it was 5$ per poll (or 0.00001$) I would not argue. That is solely the author decision, either you agree and use the product, or you don't and quit using it. It is in his perfect rights to charge whatever he wants for the bot. I just wanted to know what the options were. :)