I have some small spaces in my 1925 bungalow that are in need of insulation.  There was faced fiberglass stapled to the 2x4 rafters but that seems a bit inadequate.  How can I do this job on a budget?  I don't have money to pay someone to spray foam insulation, which would probably be best.

Could I nail 2x2 to the 2x4 so I effectively have 6 inches I can fill with (unfaced) fiberglass?  Then possibly put some type of hard insulation board over the top?