Is this is a good offer on a home?

My family is looking into buying a villa at Wild Dunes (near Isle Palms, SC). We have decided that later on this year we will make an offer. The home is listed for $524,900, the home was last sold for $480,800. It has NOT gone thtough any major renovations since the current owner has had It.The surrounding homes that are similar are all significantly less..... Mid 400's and high 300's. What do you think would be the lowest possible price we could offer?