费
fèi · HSK 3
spend
💸 弗 (not) + 贝 (shell/money) — money that's gone, i.e. spent
费 decomposes into 弗 on top (a negation) over 贝 (the ancient shell-money radical). The money is no longer there because it has been spent or consumed — hence cost, expense, fee.
费 — 弓 bow + 弗 (phonetic 'fú/fèi')
费 is a phono-semantic compound. The bottom 贝 (cowrie shell, ancient money) gives the meaning 'cost/expense,' while 弗 on top supplies the sound. Originally it referred to spending money or wasting resources, and today it means 'fee,' 'expense,' or 'to consume.'