Several parts combine into one character.

費 is a phonetic-semantic compound: 弗 (fú, "not / to brush away" — originally a pictograph of arrows being aside) on top + 貝 (cowrie shell / money) on the bottom. 弗 supplies the sound (fú → fèi) but also a hint of meaning: money being scattered or brushed away. The composite reads as "money dispersed away" = expenditure, expense, to consume. Curiously, both components have monetary associations: 貝 directly via cowrie shells, and 弗 has come to be used as the Sino-Asian phonetic transliteration of the dollar symbol $ in financial writing. Mainland simplified to 费.

Korean reading "bi." 費用 (biyong, expense — basic financial vocabulary), 消費 (sobi, consumption — economic term used in 소비자 sobija "consumer"), 浪費 (nangbi, waste / wasteful spending), 經費 (gyeongbi, operating expenses — used in business and government budgets), 學費 (hakbi, tuition — major topic of Korean educational discourse), 會費 (hoebi, membership fee). 비 vocabulary saturates Korean economic and accounting language.

Mandarin fèi, 4th tone (simplified 费). 费 (fèi), 费用 (fèiyòng, expense), 消费 (xiāofèi, consumption), 浪费 (làngfèi, to waste), 学费 (xuéfèi, tuition), and the conversational 免费 (miǎnfèi, "exempt from cost" = free of charge — top-frequency adjective in Chinese commerce: 免费送货 free delivery, 免费试用 free trial). 免费 has become essential vocabulary in the Chinese e-commerce era.

Japanese on-reading ヒ (hi) — 費用 (hiyō, cost), 消費 (shōhi, consumption — used in 消費者 shōhisha "consumer"), 浪費 (rōhi, waste), 会費 (kaihi, membership fee), 経費 (keihi, operating expenses / business costs). Kun-reading ついやす (tsuiyasu, "to spend / consume / expend") — 費やす (tsuiyasu) — used metaphorically for spending not just money but time and effort: 時間を費やす (jikan o tsuiyasu, "to spend time / use up time on something"), 努力を費やす (doryoku o tsuiyasu, "to expend effort"). The verb retains a slightly formal, written-register feel.

Memory aid: money (貝) plus 弗 (scattering / not staying in place) — money dispersed away = expense.