Pay Per Call Pricing

I was considering doing leads for local realty (lol). If i can actually somehow rank a landing page (with such intense competition)that directs calls to a local realtor , how much do you think I should charge per call?

Also, what are your thoughts on what types of keywords I should be looking at for such a niche? Eg. "homes for sale in Xx" "Xx realty" "Xx Realtors"

Since realty is probably a terrible idea for doing pay per call. What other niches could you guys recommend?