Allright since i've been recieving a lot of PM about how i solve the
PayPal stuff i will make tutorial on my website so you go check it out

And the tutorial will be about how to make the payment process let's say
the client pays on paypal, automatically the script on server will contact paypal
and sell the client and email with a 24 hours or any time you want for the link of download to expire.

Please visit www.atwa.com.mx for more info about the tutorial!