While cleaning out an old closet, I came across a box full of old baseball, hockey and football Buy Drugs Without Prescription cards. What is the best way to find out if they are worth anything?

i have a lot of unique baseball cards and would like to know where i can sell them to get the most money out of them. i have mark mcgwire cards, barry bonds, alan trammell, jim abbott, jose canseco AAA, nolan ryan, and many more. i also have some football cards too. i have anniversary cards, tops cards, Propecia buy rookie cards and all-star cards.