Zoho payments

Hi there,

I have a few questions.

1. How come Zoho payments doesn't allow cents but only accepts who dollar values?
2. When choosing payments, it only allowed a fixed dollar value. How do I changed it to variable?
3. How come I can't make form field rules with payments? Eg. I have a free product and if they choose another product from the check box, it open up the payment option.