When user come to this page, check what package a user got. Allow or deny according to package.

As for allowing download quota is not a good idea as you can't make sure a user able to download a file completely or not, user clicked a download link, he clicked cancel, still it count as download or he get disconnected during download, he have to start again.

If you want to allow download for a package only, we can do it for $5, this won't count number of downloads, if needed we can do, but download count won't be accurate as there is no easy way to find if a user have downloaded a file completely.