Like most Magic: The Gathering cards, the value of Vampire of the Dire Moon 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 (Core Set 2020)
If you want to get ahold of the original Innistrad printing, itll set you back $9
These are crucial to get you to the three spells in a turn that you want for Stellas spell copy payoff
Japan has a lot of Pokmon centres (I think about 16 at the time of writing this) but theyre constantly adding new ones (and producing awesome promo cards) meaning if you arent visiting Tokyo, youll probably still be able to find one pretty close
What to do next: Once youve gone through and searched for the value of your Pokemon cards using the mavin.io price guide, you have several different options: If the Pokemon cards are valuable: You can either hold onto the cards, perhaps get them graded if theyre really valuable, and hopefully see them appreciate in value over time