I'm doing mine now. Putty knife and elbow grease, cheap but some blood loss. Next, cheap solvent to cut the oil stains a little. Knock the loose rust off and wire wheel the big open areas.Wear saftey glasses, the little wires usaully come flying off at 300 mph. Then paint on good ole Ospho.( Phosforic Acid mix) let it dry over night, turns rust black and seals it for painting.It does'nt look to bad and after all you said cheap.That's me grin

'36 Tall cab Chevy 1.5 ton, '36 Low cab Chevy 1.5 ton, '53 GMC 2 ton, '51 GMC 640 5 ton, '47 Dodge 2 ton, '42 GMC CCKW 353 6X6.