How much can I ask XPost from /r/puppet

Hi /r/linuxadmin I come to you with a weird question that hopefully doesnt violate any rules or put anyone off. I've recently been given the opportunity to work part time for a company getting them setup with a puppet system that follows best practice and is easily maintainable. Now this part is easy, I've read the books, taken the classes, and use puppet every day as the main architect for my current company. So here's my actual problem. How much can I charge within reason without asking for too much but still getting what I deserve for my expertise? If you have any evidence to back up your claims that would be amazing, but just earmark numbers are cool too.

Thanks