Aim for old AGFA and ANSCO "PD-16" Folders, alot of them came with decent little lenses that cover 6×12 easily, not exactly wide, but you can get a cheap Anastigmat with a self cocking shutter.
For cheap wides to cover 6x9, why not a 65mm angulon? Or a 75mm Topcon or Fuji, under 200$ and something a little more solid when it comes to clinical performance.
Wollensak even made a cheap 65mm f8? Of thereabouts. I believe it was labeled a Raptar in a Graphex Shutter.
Have fun!