It shares the tenth spot with one other card
Darkrai-EX BW46/101 - BW Black Star Promos Holofoil Darkrai-EX BW46/101 - BW Black Star Promos Holofoil The Pokmon Company Each of your Pokmon that has any Darkness Energy attached to it has no Retreat Cost
We dont recommend spending your duplicates, specifically your rarest cards, just to buy a new style of playmat, card sleeve, backdrop, or coin, as you can get them by other means like events
This one has the upside of not costing us a card from hand, which is nice
If you can't get the Secret Lair directly from Wizards, you might find the products on the secondary market, and a sealed one should retain all marketing components, including a potential card with your code for digital versions
If a booster pack set is removed from Pokmon TCG Pocket, you can't open more packs or redeem your pack points for that set