Create a website pretty much like PTC (paid to click)

I want to start a new website that relates with the already known PTC concept. I know there are other PTC scripts out there, but they don't suit my project. So, i need someone able to just change and work on those already created scripts (if the code is accessible), or just simply start a new one from scratch. I prefer to pay a fixed price, but if i like your work, you could be my paid coder for that website (i would call you every time i need some changes) and, in that case, you would be paid hourly.