Does this site pay for replies? If so how?

It's all free, all volunteers.

https://www.askmehelpdesk.com/faq.php?faq=vb_board_usage#faq_support_member

This should answer all of your questions! I would not count on receiving much, because as far as I can see, only 20-25% of answered questions ever get rated, or even a reply! So receiving a cash reward or tip would be a rare occurrence. I answer questions because I like helping people, and not for monetary reasons, though a little money here and there would be cool!