For nothing; for a petty sum. For example, For two cents I'd quit the club entirely. Similarly,
like two cents, means “of little or no value or importance, worthless,” as in She made me feel like two cents. The use of two cents in this sense is thought to be derived from a similar British use of twopence or tuppence, which dates from about 1600. The American coin was substituted in the 1800s, along with two bits, slang for 25 cents and also meaning “a petty sum.” Similarly,
put in one's two cents or two cents' worth, meaning “to express one's unsolicited opinion for whatever it is worth,” dates from the late 1800s.