I was not trying to be rude with my above statement, if that is they way you took it, merely asking why you were starting so many websites related to the same content

(which you provided an answer for).
If it is the money you are worried about, personally, I would consider raising the price. Chances are if they are willing to pay $500/month, they will pay more as long as the traffic is flowing (from what you said, it seems to be).