ok so i have some yu-gi-oh cards and magic cards but i dont know anything about them how do you determine how much they are worth? and how do i sell them ?

I would recommend figuring out how much they are worth using various websites. Get some game also has a "Buylist" function on thier site you can utilize before coming and save yourself some time. Just be very careful with editions, and whether it is foil or not.

You can find how much they're worth online or in the store. To sell them all you have to do is bring the cards in question to the register and say you want to sell them