Oscommerce freelancer for website upgrades

I am looking at taking on a freelance oscommerce developer to do the upgrades to our oscommerce site and any bug fixes that come along. Work will be discussed and priced per job and agreed via skype as and when work crops up. We are looking for a cheap hourly / per job rate and the successful freelancer will gain all updates and bug fixes for our site. Usually the job will entail uploading a new oscommerce add on after which we will take on the project and alter the back end. Most php and back end work will be done by ourselves , including basic jobs like changing images and updating product information but all other php editing and add on uploads will be offered to the developer.