Like most One Piece TCG cards, the value of Soul Pocus depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Starter Deck 7: Big Mom Pirates)
Cards that create subgames have long been regulated to the Un-sets given their absolutely wild approaches to the game
Mastery Pass If you buy the Mastery Pass for a particular set, you can get one regular and one exquisite card sleeve (assuming you hit the associated Mastery levels)
Amazon: Reliable but Limited Amazon provides fewer options than eBay, but still, it's worth checking periodically
Cultivator Colossus Theres almost no better way than Cultivator Colossus to get every land from your deck onto the battlefieldwhich works great, considering it relies on the number of lands you control for its base power and toughness