Talk is cheap 意為「開空頭支票；隨便說說而已」。這個慣用語於 1800 年代開始使用至今，但確切起源不得而知。
1800 年代流行的成語中有幾個是以 talk is cheap 作開頭，如 talk is cheap but it takes money to buy a farm、talk is cheap but it takes money to buy whiskey、talk is cheap until you hire a lawyer 等等。
由於大家對上面各成語的後半段太熟悉了，因此往往略而不提。現今這些成語或慣用語都僅剩下前半段，亦即 talk is cheap，而後半段幾乎已被忘得一乾二淨。
例句：
- My boss keeps saying he’ll give me a promotion and raise, but talk is cheap. (我老闆一直說他會給我升遷和加薪，但他亂開空頭支票)
- My husband has been promising me a new washing machine for three years now. Talk is cheap. (三年來我先生一直保證要給我買一台新的洗衣機。他隨便說說而已)