My dad used to say he remembered stores used to be closed on Sunday in his day.
Since I am LDS (Mormon) we are strongly encouraged to keep the Sabbath holy and not to spend money. There is even a children's song about preparing on Saturday for the Sabbath, so we don't have to work again until Monday.
The Sabbath begins Friday at sundown and ends Saturday at sundown. That has never changed, and never will.
Please don't refer to Sunday as the Sabbath because it is not the Sabbath.