Tiki Sam is shop keeper that runs the Tiki Hut. Mickey can buy things from the Tiki Hut to help him with his adventure. He is shown to be a cheapskate, this trait being highlighted more in the sequel.
One of the quests that Sam gives Mickey requires him to locate three Tiki Masks and return them to him in exchange for the Ship Wheel. If all three masks are brought to him, he gives Mickey the Wheel along with a discount on everything in his store. However, if Mickey does the "same mask twice" trick and brings the other masks so that Sam gets four masks, he'll realize he's been tricked and gives him the wheel out of frustration. And as expected, no discount. Sam will also be rude to Mickey every time he visits the shop.