I actually have a video software and
found that by giving them a full working
version (same as you would sell) this
seems to work for the serious affiliate.
Of course you run the risk of someone
just wanting a freebie with no intention
of promoting it, but I guess you just have
to pick and choose your battles.
If the product is good, people will see it
and you will build instant credibility with
that person.
Sounds pretty simple, but it has worked
well for me.