I've developed software that manages invoices, products, customers, and sales. The price of the license is 3.500$ and can be used by three users only on Microsoft Windows operating system. After the first year, one must pay 30% yearly (a ratio that everybody use) for bug fixes and mail support (actually it costs 750$).
Now I'm rewriting the software, and will host it on the cloud. I know I can't ask 3.500$ for a license, so I'm going to ask a price per user per month.
My reasoning is to have an annual revenue while the clients keep using my software: since there are (nearly) no bugs, I don't like the idea that clients continue to use it forever after only paying the initial 3.500$. Competitors with similar, but buggy, software charge their clients for yearly support.
Is there any ratio that I can apply to determine the price per user per month? If they get bug fixes, the same level of support, and all the advantages of a cloud service*, would it be fair to set the price at 20$/month x user? For example 750/3 users/12 month)? Should it be a lot less?
(* Cloud services offer automatic backup, nothing to install, automatic updates, access from mobile devices and any operating system)
The cloud costs me 25$/month. I think I can add some clients on the same server before the performance goes down.
Thank for any advice.