Dowloads cannot be free, someone invested money, and wants to be paid for his work. However, you can get live preview of what you are paying for. My credit business model, that I've suggested, values each download in cents.

rename filename and get 100% , its what people will do ,we dont like to share our money remember this
yah, well, because of people like you hardcore on each side, evolution of internet slowed down.
However there's a solution for that too.
Your file gets licensed, and you don't get 100%.