I checked out the DigitalOcean marketplace but it looked like there are only open-source applications there, or it was really confusing how you can publish a premium script there.

That being said, userTrack does provide a cloud-init configuration for one-click install (which works on DigitalOcean for example). So currently, if the VPS provider supports images and cloud-init, you just have to select a LAMP image, paste the userTrack cloud-init and the VPS will spin-up with a functional userTrack dashboard running on it.

I have also considered sharing it as a Docker container, but that makes it slower to install (have to share the full image) and there is again no easy way to share premium Docker images, as you have to host your own Docker repository.