Big Crown: Showdown

The cheapest hat goes for 20 coins, (there are a handful of 20 coin hats). Simply play enough to collect 20 coins, once you've done that, return to the main menu and select local, then swag and purchase one hat.

I recommend boosting the 20 coins locally with a 2nd controller, that way you don't need to fight over the coins and you only need to collect 5 chests worth, as there is always 4 coins to a chest.