You might look at Harbor Freight, I bought a DC voltage pump something like that one for $45. It has a metal head, not sure everything is food grade but for a quick transfer I can't see that being an issue. I bought mine for a CIP system but it didn't have the head pressure to push the spray ball.
You might also try a weldless ball valve on your fermentor and a March pump. Then you'd have a more versatile pump.