益金[ekikin] profit
益虫[ekichuu] useful insect
益鳥[ekichou] beneficial bird
益友[ekiyuu] good friend
過剰利益[kajourieki] excess profit

共益[kyoueki] common profit
共益費[kyouekihi] monthly fee for common areas of an apartment building (lighting, etc.)
権益[keneki] (one's) interests
公益[koueki] public
公益事業[kouekijigyou] public utilities

御金[okane] money
金糸雀[kinshijaku] canary (esp. the island canary, Serinus canaria)
違約金[iyakukin] penalty for contract breach
一刻千金[ikkokusenkin] every moment is precious
一字千金[ichijisenkin] word of great value

一時金[ichijikin] lump sum
一時賜金[ichijishikin] lump-sum grant
引き金を引く[hikiganewohiku] to pull the trigger
引当金[hikiatekin] reserves
隠れ借金[kakureshakkin] hidden debts