Is it possible to install IPC without CRM?

Dear guys,

I've requirement from business department. They want to let their customers can place sales order in self-developed web application. but the product is variant configuration and customer can select product configuration step by step like in sap.I have asked help from SAP company , and their feedback is, I have installed CRM sales and IPC together. but we don't use sap CRM at all.

We just use ECC 5.0, do anybody know how to use IPC easily for this situation? I've heard about IPC 4.0,IPC50, AP7.0... not sure which one can be used for my case..

How about the cost?

Thanks in advance.

best regards,

Toby