Two key factors determine the value of a football card:
Demand
Condition
Several things affect the demand for a card, including the card’s age and the number of the specific card that were printed. The player featured on the card also plays a huge role. Collectors tend to focus on cards featuring high-profile players. A card’s overall rarity is important too, as rare cards offer low supply, making it more difficult for them to meet demand.
Condition can make the difference between a card being worth a few dollars or several thousand dollars. Some organizations, such as the PSA, grade cards based on their condition. The closer a card comes to the Gem Mint 10 rating, which means the card is almost perfect, the more it will be worth.