So about $40 if you want to recreate one map sheet that would be about 34 by 38 inches. But if you wanted a 2 map game, we're talking $80.
Now for a 4x4 foot board for Alpha Strike, you'd need 7 sets if my math is right. That's not too bad considering the cost of the fancy vinyl game mats that seem to be becoming a thing lately. And this is customizable. I think i'd probably just go with a green table cloth and then buy a water and road set or two.
EDIT: A GREEN table cloth. A "great" table cloth would be nice, but it would need to be green. Or grey for urban battles I guess.