I've found quite a few free patterns that work like that. Probably partly because the pattern maker is already set up with a store, and partly so they can track how many people download what.

Also, I've found that those patterns often come with a "For the exclusive use of [Name] [Email address]" watermark on the bottom. Which makes it easier to print at a copy shop or copy 'n' print center.

Sidenote: I've never had to enter payment information if I check out with only free patterns. Maybe my name, address, etc, but not my credit card.