Not a lot of value, from your description. Without pics it's hard, but the range for what you describe is about $20 to $40 each. In good working order, about $75 -$90 each.
Working on Benjamin pistols is not as easy as the Crosman models. It takes some special tools to pull the valve, for one thing. Certainly not impossible but just a step up from working on the Crosmans. Parts are avaiable: Precision Pellet and others will sell parts.
I would suggest sending them off to MAC-1 and have an expert bring 'em back to life. Hard to buy a better air pistol today.