Once you've accumulated tradeable players by opening packs, you can begin to sort through them deciding which ones are worth selling on the transfer market, and which ones you'd be better off quick-selling.
You can put up a card for sale on the transfer market if you think someone will buy it for more than its quick-sell value. However, if you think a card won't be bought then use the quick sell feature to discard it in exchange for FC 24 coins.
There are two major methods to invest in the EA Sports FC 24 Transfer Market:
Buy cards low early in the week and sell later in the week when people are building Champions teams.
Buy cards that might increase in value due to another variable such as:
The player will receive an SBC version or Special Promo Card.
The player is a top choice for a newly released Evolution.
The card will receive an upgrade based on the player's real-world team performance (Road to the Knockouts, etc.)
Each of these methods can be used to great benefit but requires careful study of the market to know when is a good time to buy and sell.