Depends on how you think people will act. Let’s say the household income is 100k, at 20% down (30 yr, 6.5%) a mortgage of about $2200 monthly is doable (~28% of gross income), which leads to a house price around $440k, but if only 10% down then to stay at that monthly mortgage the house would have to be about $390. Basically this is what would be “affordable” with that income at those down payments. It could always go lower of course.