I've had to move a couple of times since I bought a safe so hired professional movers to move it. It was right at $150 per move (in town) and worth every penny. I only had a couple of steps to deal with each time, but the movers used a heavy duty appliance dolly with straps and didn't have any trouble with it.

I've since moved it myself from one room to another both with a dolly and just sliding it on carpet. I wouldn't consider moving it my self if I had a basement to deal with...