Deliver zips daily

Feel free to move this thread if it does't belong here, but I thought it was the closest match.

I want to start a service where I deliver each user a 5mb zip file a day (probably 300 users).

How could I do that?
Putting it on FTP and distributing the link is not an option, cause I want to watermark the files to have some means against abuse and leakage.

Are there email programs out there that would do that on autopilot?
Thanks!

You could have a script made that will automate all this. Most files types are susceptible to watermarking without getting destroyed and emailing is easy. Why not make a post on the "hire a freelancer" section to get someone on it?

Also, instead of mailing, you could have a "members area" with separate login per customer.

I hoped there was a proven solution like email autoresponders or something like that. Watermarking would happen to the data. Data are large lists, so I could insert one special entry for each user on his zip, I would do that while processing the data anyway.
I scrape the most interesting parts of a major site with a selfmade bot daily (with URL of offer, Image URL, and lots of data to find bargains and interesting stuff). Wanted to offer access to the data for money.

Very deceiving thread name... I thought someone was looking for someone to deliver ounces of marijuana lol.