A point to note, if you do 'buy' a plot from another player, it's honour-based. I don't think it happens often, but there is nothing to stop them disappearing with your gil when you hand it over and not relinquishing their plot. I believe trading plots is frowned upon by SE (not sure if the ToS expressly forbids it however) so if the worst happened, a GM might not be very sympathetic. Also you'll need to have enough Gil saved to pay the other player their asking price AND to buy the plot itself when they relinquish it. They can't actually trade you a deed to that plot in exchange for your gil