The Arrow Sign is a small static decor item. It is part of the Museum Set, and therefore can be obtained from the Museum Shop for 3,500 bells. It can be sold for 875 bells at Re-Tail (700 Bells at Nooklings).
Customizing the Arrow Sign costs 350 Bells. To return it to its original state, it costs half the price (175 Bells).
There are 2 options in customizing the arrow direction.