How to create branded URL like

I have a product like sales automation software web/mobile, till date I have few customers and each of them have separate database and code directory on my shared hosting and managing them by creating subdomain.
The challenge is that we lost Inodes of maximum inode limit provided by the server and service provider is asking to update previous plan which costlier.
Now I have more lead to onboard the customers but it seems that this process is expensive process for us like server costing increased and code management getting more complex that will cost us higher than earning.
I actually want the process like anyone can visit on our website and purchase the pack off services and redirect them with virtual sub-domain and multiple customer can signup and can access the functionality accordingly with same same database and code directory.
My expectation like like etc.
Please guide us for achieve this milestone.