When Microsoft introduced Small Business Server 2008, it upped the price of the base package and reduced the cost of client access licenses.
That’s OK for the, umm, larger small business; but it’s made the product expensive for those tiny setups who only need 5 or 10 CALs.
RIght now, ebuyer.com is offering SBS 2008 Standard for 835.49+VAT and an OEM version for £535.55+VAT.
By contrast, you can get the old SBS 2003 Standard OEM for £275.90+VAT.
Suitable servers on the other hand are now at rock-bottom prices. If you are lucky you can pick up an HP ML110 for around £200+VAT (try Amazon). Of course you have to add some RAM and probably a second hard drive for RAID, but neither is particularly expensive.
The 2003 edition was better value. This has also made Linux more attractive for those with the skills to look after it, and businesses that are not saddled with Windows-only software that has to run on the server.