How to sell hosted web application?

Hi everyone,

I created a web app. I want to give the script away in a Fremium model, but also I would like to offer a hosted version.
Do you know a shop system that automatically installs files and setup a new Database on my server after a client booked my application? Did not really find something with google or on codecanyon.

Or would you recommend to write that by myself? i would prefer to use someones else shop script that for but if there is anyone who would like to setup something alike in a team please contact me. 

Every comment is appreciated!
Thanks! Jan