In the scenario given, I probably would buy from the cheaper place, since I can still return the item. But if shipping fees are involved at the cheaper place, I would probably buy from the more expensive place for ease of return, since I am extremely picky about fit and end up returning a very large proportion of what I try on. I would probably be willing to pay maybe 20% more.
Generally, a "return anything at any time in any state" doesn't mean a lot to me as opposed to a shorter return window. I am always good about returning items within a couple of weeks of receipt, regardless of how long of a return window I have. The only time "return anything at any time in any state" means anything to me is when I am buying makeup or hair products that might not work out, or when I am dealing with a brand with a history of spotty quality.