[AngelicaDeAlquezar]

@Hola: It depends on what persona B meant: if the sold thing was expensive, then I would rather use "...y valía mucho" (to keep the verb "valer").
If the object is rather what Chileno has interpreted as "it was worth it", then I suppose "lo valió mucho" is correct, although a bit odd for me. I would have rather used "...y valió mucho la pena".