I have had affiliates ask this time and time again for one of my products.
I run a MEMBERSHIP site that's only a pittance to join. And I have always heard that it is best to promote products that you have purchased and you like and really believe in.
I just tell them to pay them money, come in and have a look around, and if they find it's valuable enough, they should promote it.
A few have done so then ask for a refund. Most don't ever sign up.
What do you do?