What is her strategy when playing the deck? Does she use the BREAKs or Megas more often? Try to hard counter that aspect. However, I think you should just play a consistent deck. If you can play a deck that can hit relatively high numbers, about 100, without to much effort (passmissian, gyarados, most EX decks), you should outspend her the entire game. If all else fails, buy a worlds deck and sleeve it up, and hope she doesn’t notice. Good Luck!