Depending on the rarity and if it is holofoil. There worth no more than US Pokemon cards, there acually worth less due to the Mony diffrence, to sell a Pocket Monster card here in the US you wont get...
There are several possible words for monster. Obake (お化け）is "something changed", i.e. something not normal, unnatural. Bakemono（化け物）is the same thing, with a different expression....