Webcams.com affiliate program would be a safe start, good lifetime revshare or high PPS. Loads of webmaster tools. How much average people spend is hard to say since It's dependant on your traffic and how willing they are to pay, members area traffic is always good. Most shows are 1 on 1 but there are those with several people involved too.
Check them out and hit up Daniel or Jago to get all the info and tools you need.