It sounds like you're discussing a method related to gaming, likely involving sports games such as Mut 26 coins, where players can be bought, sold, and trained using in-game resources like coins or training points. Here's a breakdown based on the context:

Buying and Selling Players: Players can be purchased and sold within the game's marketplace. The strategy involves buying players at a certain price and then selling them later for a profit, although it sometimes requires trial and error to find the right players and prices.

Returns on Investment: Not every player bought and sold will yield the expected returns. It takes experimentation and learning from experience to understand which players are profitable.

Training Points: Training points seem to be a valuable resource in the game. One effective method to accumulate a large number of training points involves buying and selling players strategically. This method requires a sufficient amount of in-game currency (coins) to begin with.

Quickselling Cards: As you progress, you can quicksell (sell quickly for in-game currency or other resources) the cards or players you earn. This generates more currency that can be reinvested into buying more players or used directly for training.

Grinding: This refers to the effort required to accumulate the necessary resources (coins) through gameplay or other in-game activities before being able to effectively use the buying and selling strategy.

Overall, this approach combines elements of strategic trading, resource management (coins), and optimizing Mut 26 coins for sale player performance (training points) within the game's ecosystem. It's a common gameplay strategy in many sports simulation games with trading card or player management features.