I usually put up a milestone date and direct them to that date, quite a few times have to push that date to work on stuff that pays my bills.

The best ones who pay are those who directly reach out with a paid offer; which shows that they definitely have explored the market (most likely than not) and you are the best option :). The better than the best and great to work with clients are those who just reach out to you directly, only very rarely would happen!!!