Hi Pratap,
As Jan has indicated it is too broad a question. I can just give you some pointers on the way the costs may be arrived at:
Remember, I am just a regular consultant working in the field of SAP[fairly long though] who does independent consulting. You dont have to take my word for it.
SOFTWARE:
Usually it is based on the number of user licences and each module could have any number of users based on the customer. I am pretty sure there are other models now;
HARDWARE:
Dont have much inputs on this.
OTHERS:
Deployment / Implementation of the software to suit the customer's requirements would be the major part of others to big with. This would entail engaging an Implementation partner. This could also be a substantial amount.
The Implementation Partner services would be either on a fixed bid or T & M basis.
Depending upon the number of resources and hours they work for the duration of the project the amount would be spent.
In a fixed bid, as the word says, the implementation partner would quote a fixed amount for deploying the SAP Solution for the customer, irrespective of the number of resources and time the project takes. This is a kind of risky proposition if the complexity of the project are not known upfront.
There are other models now a days like Rapid Deployment[based on the size of the company and how much project scope the company wants to have] which deals with shorter cycle of implementation and hence lesser dollars spent with standard or close to standard SAP Process mapping. These are I believe fixed bid assignments. I do not have the current understanding on this as it has been a while since I worked in one of them.
I am pretty sure there are other methods too, but I am limited to my knowledge above. Hope this makes it a little easier in terms of general introduction to this complex process.
Thanks.