I believe there is a directive from Equity about rates that Actors should be paid by students. CastNet have a contract that you can print out for student films, so that if you do waive the fee they guarantee a VHS/DVD copy and if that has not been forthcoming within 90 days (or an agreed time after 90 days), then you are able to invoice them for the Equity rate. I recently did a short film for a 16 year old student. He gave me £20.00 for expenses and when he couldn't send me a DVD copy, he sent a VHS instead and many apologies. So there are some very nice students out there.