there's no such thing as a free lunch

The phrase "there's no such thing as a free lunch" is an idiom that suggests nothing is truly free or that everything has a cost or consequence. It emphasizes the idea that even if something appears to be given without charge, there must be a hidden catch or obligation involved. In other words, anything claimed to be "free" is believed to have underlying costs or trade-offs that may not be immediately apparent. The phrase is often used to express skepticism or caution when something is seemingly offered at no cost.