My experience was the used ones run right up with the new ones, the Walker is so imposing a weapon that I think the used prices reflect that. one shot a lot and nicked a little will go for $300-$350.
I've seen a couple go cheaper, but seldom.
NRA, VCDL, USAF 1970-76 6200FMS CLARK FIELD,P.I.'71-'72- 18 SOS, NKP, THAILAND '72, BASE FLIGHT,KEESLER AFB,MISS '72-'74, CARSWELL AFB,TX '74-'76