yugioh cards cost Rulings - What is a cost? The levels of all of the Monsters in your hand are reduced by 2 until the End Phase of the activated turn. YuGiOh Trading Card Game Spell

After you attack with a creature with boast, you can pay to activate its boast ability once during your turn

1 Twilight Masquerade Booster

Stay safe and have a good one

Echo (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.) When this creature enters, return target creature card from your graveyard to the battlefield

For a good look at the actual probability of getting some of these super rare cards, we have done some math below

Serperior #125Secret Rare $149.20 Serperior #13Holo Rare $5.06 Serperior #8Holo Rare $2.18 Serperior #RC3Uncommon $4.58 Serperior #7Rare $0.65 Serperior #6Rare $0.15 Serperior #6Rare $0.26 Serperior #7Uncommon $2.39 Serperior - 064 #64Promo $8.65 Serperior - 064 [Staff] #64Promo $27.39 Druddigon #TG9Ultra Rare $4.40 Kricketune V #TG12Ultra Rare $5.27 Blaziken VMAX #TG15Ultra Rare $38.84 Corviknight V #TG18Ultra Rare $15.99 Milotic #TG2Ultra Rare $9.27 Rayquaza VMAX (Secret) #TG29Secret Rare $38.22 Duraludon VMAX #TG21Ultra Rare $12.86 Friends in Galar #TG23Ultra Rare $9.85 Judge #TG25Ultra Rare $7.31 Zeraora V #TG16Ultra Rare $12.77