Informal. Typically used in a negative context to imply that the person in question deserves whatever negative happened to them

You got a speeding ticket? It serves you right! Maybe that will teach you not to speed

Hai preso la multa? Ti sta bene, così impari a correre in macchina

You got ripped off? It serves you right! You just do whatever comes into your head and never listen to someone who's has more experience

Ti hanno imbrogliato? Ben ti sta! Fai sempre e solo di testa tua e non ascolti chi ne sa più di te