To protect your unique business model, I recommend including specific clauses regarding:
Service Model: Clearly define that the "Zero Upfront Cost" applies only to development and is contingent on active hosting on your servers.
Infrastructure Rights: Since you provide the code and the hosting environment together, define the terms of site migration or termination.
Payment Terms: Details on the monthly/annual subscription fees for the Standard, Professional, and Business tiers.
Prohibited Content: A list of activities or content not allowed on your high-speed cloud servers to maintain security for all clients.