Meaning of the word "the only free cheese is in the mousetrap" in English

What does "the only free cheese is in the mousetrap" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

the only free cheese is in the mousetrap

US /ði ˈoʊnli friː tʃiːz ɪz ɪn ðə ˈmaʊstræp/
UK /ði ˈəʊnli friː tʃiːz ɪz ɪn ðə ˈmaʊstræp/
"the only free cheese is in the mousetrap" picture

Idiom

used to say that nothing is truly free and that there is always a hidden cost or catch to something that appears to be a gift

Example:
He offered me a free vacation, but I remembered that the only free cheese is in the mousetrap.
Be careful with those 'no-strings-attached' deals; the only free cheese is in the mousetrap.