What if the startup says that in case if it fails or shut down, it will make the source code public? Even in that case, it will be quite tedious and challenging to host the application due to its complexity.
Will you be willing to spend some bucks (like 6/12 months subscription fee in exchange of the code?) so that there is no forced-commitment/attachment with the platform and you can host it yourself as and when needed.
We are planning to charge around $25 - $250 per month, depending on the traffic volume. All features will be available in all the plans.