it varies - the first referral is $250 in disney dollars, or dues payment or gift to a charity (you don't get the donation in your name - so no tax deduction)
it goes up after that until you have 5 referrals.
but if your state allows pay out - definitely recommend your DVC guide - also give them your name and state - so they can find you.
It depends on where you live, too. Some states (like Maine ) don't allow it, so though we've referred a few people, and at least one family who bought DVC, all we've received is a nice thank you note from our guide.