If by a couple you literally mean 10 or under, yeah they’re pretty much valueless. Unless the card is one of the ultra rare cards (black lotus or mox ruby or time walk) it probably isn’t worth your time to price them. By all means consult an online price guide, but do realize that not everyone nor every card dealer values the cards the same. Your easiest way to convert cards to money is to take them to a card/comic book shop and take whatever they give you, which probably won’t be much. You can also sell them as a lot online via eBay or craigslist, you might get more money but you’ll likely spend more time and effort.