Adding a bathroom on main level - cost / plan?

[Chou D.]

Hey everyone, first time home buyer here. I'm looking at purchasing a property that doesn't have a bathroom on the ground floor. What would be the best place to add a powder-room or a half bath, and how much would it cost? There is no basement and the foundation (under the flooring) is concrete slab. It looks like there's no plumbing apart from in the kitchen area, which is used in the second floor bathrooms as well.