Where to but used carts?

I’ve been looking to get a cart for hauling gear that can fold up and fit into my smaller hatchback Impreza. I’ve landed on either the cosco hand truck or a Remin Kartmaster HD500. Of course I’d rather have the Kartmaster and would buy it but I’m moving to Boston this month and can’t really afford to heavily invest in gear right now. Is there somewhere I could pick up a used Kartmaster? I’ve tried looking online but can’t find one anywhere. The cosco cart seems alright but it’s not nearly as compact and probably won’t last as long. I know the Kartmaster will last a long time. Also I’m not a fan of the RocknRoller carts. They have their place but it’s always a struggle loading those rickety things and I don’t trust them.