Recently, we were estimating a solution for our customers. They want a Sharepoint (WSS 3.0) solution to be installed on a dedicated server and then used by their 100+ employees (they do not want to install a box in their own domain because don't want to bear additional administrative expenses, and don't want to pay too much for hardware, while renting a dedicated server will let them safely starts with small monthly payments for the hardware.
We were to find the cheapest solution with as less licensing costs as possible
The licensing politics of the Microsoft is very tricky. :) First of all, they recommend Windows Server Web Edition for front end servers. It has no limits in number of users. It costs only approx. 500$. However it is not suited for WSS deployment well, because you cannot install any database except MS SQL Express there. And SQL Express is limited with 4G, but our customer expects to have more then 100 Gb of documents in WSS document libraries.
Well so we though we will have to use SQL Workgroup Edition (to store more then 4Gb) and that means that we need to use Windows Server Standard Edition. We have 100 users, so per-user licensing model of SQL Server is not good for us, but per processor license is also not very cheap. And what if we have 2 processors...
Hopefully, I find the solution that post . It tells that Windows Internal Database, that is automatically installed when you install WSS in basic mode, is actually a special version of MS SQL Express with no memory limitation !
So, we proceed with installing Windows Server Standard Edition (costs approx. 1000$) and that should be enough to deploy WSS solution on one box, using Basic setup option.