Get yourself a L2 type switch that allows you to configure ACLs based on MAC addresses.

I personally recommend cisco 3550 switch. The 3550 supports L2 and L3 functionality, however for your application/requirement, the L2 is way to go......alot cheaper. I deployed about 500 of them in last 6 month for international bank and they work very nicely..

If your looking for something cheaper, buy the lower model, either the Cisco 1900 or 2900 (although they are discontinued..Cisco no longer supports...works just as well) off Ebay..

Good Luck,,

P.S.
Configuration is straight forward.. All documentation is available on Cisco web site.