Opening Scarlet & Violet Premium Checklane Blister [Gengar] returns about $3.92 in card value against its $30.00 price — roughly $0.13 back per dollar spent. On current prices, you lose money on average by opening it.
See every card and pull rate in Scarlet & Violet Base Set
How expected value is calculated — card value only, from published pull rates and daily market prices.
Scarlet & Violet Premium Checklane Blister [Gengar] on TCGplayer