They constantly supply Badges for Mario'sshopping needs, though at one point Mario must retrieve Rowf's calculator from the Shy Guy's Toy Box, after it being stolen. Their shop opens after the end of Chapter One. Although expensive, the player should buy as many as possible, as some of the badges are one of a kind and very helpful.
A Toad in Toad Town Port mentioned that Rowf and Rhuff used to sell rare foods. The Toad also mentioned that he set up a shop in a different town a long time ago while selling rare foods before moving to Toad Town to sell badges. The Toad lastly mentioned that Rowf's wife used to work with him a long time ago in the business but ended up with no profit. The Toad muses what happened in that time.
At the end of the game, they leave to sell at another place.