Yoshi P actually announced this but price is still up in the air. Personal housing won't be out til about patch 3.8 (might be earlier but that is their take on it) and will cost players around 800,000G
Also it's unclear if it will be an instanced area or if it will be an actual house where you have a garden. It might just be like personal FC rooms (aka mog houses in XI) where it's just an instanced area you go into that is the inside of your house. No large, medium, small diff just everyone same size house and all same price value.