Sourcing/Reverse Script with modfications

I want to source out jobs to be done. Therefore, I want something like a freelance site. Can someone suggest a low cost or open source script that is not full of bugs etc which can be quickly adapted to my needs. I have had downloaded Cogzidel RBS, a free open source script but it seems problematic. I am told there is a Joomla reverse auction extension as well. Of there are other suggestions then fine. I am open to suggestion. Will pay $100 for a tested, turn key modified script.