I suggest you contact your local power provider. They can tell you more about cost in your area than we that have no idea where in the world you are located.
Are you a hobbiest or will you be doing production welding?
Something to consider though, Your power consumption (KWs)($$$) will much more with 220 volt service than with 440. But as you said not always an available option.
Will you really use the peak out put of the machine that much? If so then you local power company will be real proud of you. They might even send you a Christmas card.