I'm on PPD & I have no problem with 150 for free users & 200 for registered users.
Don't assume just because someone is on PPD that they don't worry about sales.Without sales you can't stay in business.I as a PPD user like having enough sales for you to at the very least break even with my account.And most of the time I do get enough sales for that to happen.

Right now I think the one thing you need is patience.People are getting tired of buying premium and having the host vanish a month later.So they are starting to wait & see if it looks like a host is going to stick around or not before they spend their money.