Run of the mill banner ads are probably the worst way to monetize things like that. From my POV there are two main options: 1) Build it up enough to have a pre

Run of the mill banner ads are probably the worst way to monetize things like that. From my POV there are two main options: 1) Build it up enough to have a premium tier with something people would be willing to pay for. This essentially makes you SaaS, however, with all that's involved with running a SaaS business. 2) Lead gen type sponsorships on the backend. Let's say your page is a * to PDF converter (as someone linked below), there are commercial PDF services, software vendors, etc, who would be keen to reach an audience requiring those services. Alternatively (again, depending on the service) there might be companies who have content that would appeal to such users and would pay a monthly fee to have a link to their content included on your finish/thank you page (this is common in the email newsletter signup world, related vendors like to be on those thank you pages as a next destination). For my own part, depending on the tools in question, I might even be keen on sponsoring some, and I was recently speaking with a director of marketing at an incubator who advised me the companies they represent get a lot of value out of sponsoring tools in this way.