What is the best segmentation and email marketing strategy for a real estate website?

Which type of buildings: Small flats with low costs, medium size houses or flats for ordinary mid-range people, luxury flats or villas for wealthy ones. 

If you are thinking about small flats for low costs, you are better put the emphasis of your strategy on price.

If the mid-range people has been aimed by you, you are better to have a combination of quality and price.

If your segment is of wealthy people, just go for differentiation.