Swindler is a mind game for two or more players

In the huge lines of Disneyland, my friend and I eventually ran out of things to talk about, so I created a game that doesn't require any cards, dice, chips, etc. I later refined it thanks to some help on StackExchange (https://gamedev.stackexchange.com/questions/202999/1v1-bartering-brain-game-see-any-problems/203018?noredirect=1#comment369702_203018).

Here's how it goes:

1. Find two or more players. For each round, designate one player as the buyer and one as the seller. All other players (if any) spectate.

2. Each player, think of two numbers from 0 to 49 inclusive. Say one aloud. Add the number the other person said to your secret one, and mod by 50. If you're the buyer, add 50. Keep this one number in mind. Basically this step generates a random number for each player; you're incentivized to make these as random as possible.

3. You are negotiating over the price of an item. If you're the buyer, your number is the maximum B you will pay for the item. If you're the seller, it's the minimum S you will sell it for. Haggle until either a deal is reached at price P or someone walks away. You can enforce a reasonable time or bid limit.

4. Reveal S and B to all players. If a deal was reached, the buyer scores B - P points, and the seller scores P - S points, aka the "profit." If no deal was reached, the buyer loses B - 50 points, and the seller loses 50 - S points, aka the "desperation."

5. Change sides, or rotate peers if there are more than two players. Keep track of points.

There are some parallels to poker. There's bluffing. Getting a low B or a high S is like drawing a strong hand, where you have more hidden power to exert. The no-deal penalty forces players to put skin in the game, except it's much heavier than the typical poker blinds/antes. In two-player mode, it's effectively a zero-sum game.

But unlike poker, >2 player games are not zero-sum. If there are enough rounds, players may feel incentivized to cooperate with each other so they reach fair deals instead of hurting each other with no-deal penalties.