Are football cards worth anything is usually asked about a box rather than a card, and the answer for the box is almost always no. The answer for a few cards inside it can be yes. Sorting one from the other takes three checks that you can do without looking up a single price, and then five sales for whatever survives.
Start with what the card says about itself
Look for a serial number, an autograph signed onto the card, a memorabilia swatch with wording about game use, and anything marked as a short print. Modern football sets state a lot about themselves in small print, and that print is the most reliable information you will get about how many exist.
Then the date
Football's overproduced years match baseball's: the late 1980s through the mid 1990s produced base cards in volumes that no amount of nostalgia will absorb. Earlier cards came from smaller runs and survived in worse condition, which is the combination that makes condition matter. A pre-1980 card in sharp condition is worth checking carefully.
Then whether anyone is buying
A card is worth what somebody pays, and if nobody has paid anything for one in months then there is no price to quote. Search completed sales rather than listings. Finding none is a real result: it means the card is illiquid, which for a collection you want to sell is more important than any individual estimate.
Then do the arithmetic on what is left
For the cards that do have sales, five of them through the card value checker gives the middle-three figure with the outlier visible. If you are selling, add the marketplace percentage and postage and read what you would keep, because on ordinary cards those two can be most of the price.
Questions people ask about are football cards worth anything
I have hundreds of cards from the 1990s. Where do I start?
With the inserts, autographs and anything numbered, and not with the base cards. Base cards from that decade are abundant, and checking them one by one is an expensive use of an evening.
Does a Hall of Fame player guarantee value?
No. Demand for the player is only half the equation and supply is the other half, and for most famous players the supply of their common cards is very large.
Are unopened packs worth more?
Sometimes, and it is a separate market with its own risks and its own authentication questions. This site does not price sealed product.
What condition do buyers actually want?
Sharp corners, clean edges, an unmarked surface and even borders. The gap in price between that and a card that looks fine at arm's length is much larger than most people expect.