The cheapest supercharger is the fairly common Eaton M90 but needs some fabrication to supply the manifold, and also to adapt an intake (since they are all rear mount TB).
A centrifugal is more $$$ but may be easier to mount since the output just goes to a std. carburetor.
I have found a couple Wade supercharger on eBay, they end tonight so I shall see how those go price wise. Its a tricky one as I can't find much online about rebuilding these. An m90 would be a good budget way to go but I can't get passed it looking too new being strapped to the engine, seeing as I'm trying to build a fairly strict era specific car this would be the first "new" part