These aren't technical, not gochas, they're easy questions that even the sales guy should knock out of the park.

Chances are very good that a $200 Dep Store bike has a freewheel (though you might check). Chances are also good that OP doesn't need one, and if he does he could get an equivalent wheel plus freehub for not much more (or even less) than what the shop might charge to replace a freewheel. I would want to know how the shop handles it.

I think it's a very good indicator of how a store will treat its customers.