I bought an open frame Variable transformer (Variac) from a local flea market for $5. Would need to package it for bench use so decided to use materials at home to create a variable AC supply using a Harbor Freight multimeter (free or less than $4 new), a power switch, IEC socket, fuse holder, a 9V power supply (wall wart) that I had rescued from various scrap electronics. I also made a wooden box from scrap wood (the backpanel of a shelf) as a chassis.