Rare Pokmon cards, in particular, have been known to sell for hundreds if not thousands of dollars, but it can be difficult to determine which cards are valuable collector's items and which are simply cardboard nostalgia
Other products: If the product only gives you a Promo Card, you can redeem up to four Code Cards, but if the product only gives you assets for your online decks, you can only redeem one per product
You can currently find this card for less than a dollar, but I expect that to change quickly
You might see it once in a Blue moon from someone who really wants that extra land search, but if I'm being frank: you're likely seeing a suboptimal build at that point
It doesnt work with mana though, so you cant manipulate Treasure or the mana generated by cards like Ashnod's Altar