Thanks for your post. To answer your question on pricing: The default deployment option is our public Mendix Cloud with a choice of two editions: Pro and Enterprise. Pro Edition starts at $1250 per month for an application with 50 users. Enterprise Edition starts at $1675 per month for same configuration. This includes the compute resources to run the app. Adding more users and apps will increase the price.
If your customer(s) prefer a private cloud deployment they have a choice of Cloud Foundry-based providers like IBM Bluemix, Pivotal or HPE. The Mendix pricing is identical to Mendix Cloud for users and apps, however the cost of compute resources comes extra. We are listed in the IBM Bluemix Catalog from where you can sign up for IBMs offering, Pivotal and HPE do not have such marketplace.
Same applies for deployment in virtual private clouds at AWS or Azure under your customer's account. You will be charged for Mendix subscription + the cost of resources. We are listed in catalog / marketplace of both providers.
The various deployment options are described on this page: https://www.mendix.com/deployment-options/
If you're interested in the exploring options for your customer(s), I suggest you ask for quote and we'll get in touch with you.
Hope this explanation helps.