We charge a small fee for parking in our museum's lot. For a variety of reasons, we can't charge this at the lot's entry point, and instead sell them at the front desk as well as online. We've been selling them as a merchandise item, which works fine for onsite sales. However, it doesn't work well with online sales because there's no print-at-home capability with merchandise sales. I'm considering selling these as an event, does anyone have any experience with this?

 We sell them as an event and also as a series, as we offer multiple day parking also. It works fine, online and print at home works too.