I"m looking for a way to place a film online and provide clients a unique link that they can use to download it but the link has to expire after the download had been finished, this to prevent that they will share the link further and others would download it for free. Payment doesn't have to be online, that is handled before in cash and the link is send to them by email.

Does anyone know of a service that will allow to do this, even for 100+ downloads?

I know it exists as I have purchased software with limited times you can redownload it.

http://www.us.to/

That's cool! And it's free? Will run some tests with it today, thx for the link.