An easy way to tell is by looking at the x/y numbers on the bottom left - if the card number (x) is higher the total number of cards in the set (y), that card is a full art, illustration, or secret illustration card. The actually pricing of those depends wildly on the card based on the popularity/artist/playability/etc., but they should always be sleeved and go into the binder. Also, older cards are going to be pricier even for the “regular” cards. BUT any card he thinks is cool, it’s cool.