Northwest of Reindeer is a house with an old man. Talk to him, then go to the sign below the house, then check it to find the old guy's dentures. Give them to him and he'll give you some mouthwash. After that, he'll sell it to you $10 bucks a bottle, unlike the store which sells it for it for $175, $165 more!
Mouthwash sells for $87 at the store, and only losing ten dollars from that profit, you'd be gaining money.
This is useful for gaining enough money to buy weapons.