What does the cryptic crossword clue "After payment one may let you in, at a push (9)" mean?

The definition is "After payment one may let you in, at a push". The wordplay uses a cryptic definition. Cryptic definition The answer is TURNSTILE.

After payment one may let you in, at a push (9)

Guardian Cryptic #29100 | 15 Across | 2023-06-19 flower