Mai ming xiao zi (1979)

Venom regulars Philip Kwok, Chiang Sheng, and Sun Chien star as a gang of unemployed martial artists who spend their days stuffing their faces at local restaurants and letting the staff beat them up instead of paying the bill. Their fortunes appear to improve when the head of a local security agency hires them to take out the competition, who their new employer insists is up to no good. But the boys are being played for fools, and after an unfortunate misunderstanding, they unite with their former adversary to take out the true villain.