Destined Rivals is an entire expansion dedicated to Team Rocket, the fan-favorite crime syndicate that dates all the way back to the original 1996 Pokmon games
It seems likely that players are looking to collect one of every Nazgul, so they can have the complete set in their decks
This is where Banette starts going up in price
In a standard free simulator, the cards you pull are just digital images that stay within your virtual collection on that site
My dad, for example, loved to find obscure combos and then build decks where he won by getting to cast them together
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying, add any cost increases, then apply any cost reductions (such as that of Serpent of the Pass's second ability)