If you don't cast the card, it's put into your graveyard
Sure it cost the same as three Llanowar Elves, but those are just 1/1 weenies, Sisters is a stout 2/2
However, if you are digging around on eBay trying to find the cheapest copies of Underground Sea, if you come across something that looks way too good to be true (like a copy that looks pack fresh for the same price as the heavily-played versions), it probably is too good to be true
9 Maleficent's Staff Enchanted - $101.23 A bit of a slow build, Maleficients Staff can accrue tons of lore for you over the course of a game just by hanging out on the battlefield for a few turns
Rin and Seri, Inseparable They get along like cats and dogs, huh
Even rats hoard their treasures