Japanese cards use a different grading scale than PSA or BGS: Near Mint (NM) : Cards in excellent condition with minimal wear
It does seem as if every set has a preferred trainer, and for Phantasmal Flames it definitely seems to be Dawn
Jet Medallion, Bolass Citadel, draw spells, tutors, and black cards that lack colorless requirements in their mana costs tend to work best with Krrik, as they help you stretch your mana and card access into ridiculously explosive turns that can win you the game on the spot if your opponents dont have access to any interaction
(Price doesnt really matter, as long as its not outrageous like 50 USD for a Common
Also, with cards like Wishclaw Talisman, the downside of donating the card might be obviated by you using the card to win that turn
Rare cards are harder to find and generally more valuable