It really depends on the quality you want. I could easily Alec out a 2500 square foot home that has $300k in materials alone. High end windows, flooring, bathroom materials, and kitchens aren’t cheap. A fridge and range can cost $30k+ at the higher ends. Windows $2k/each. $10/sqft premium flooring. This doesn’t include labor yet which is another $100k-$200k. All this can go on a plot of land that costs $350k. Thus isn’t uncommon in higher end developments.

Of course, vinyl windows, cheap flooring, builder grade kitchen and bathrooms bring the cost down significantly. But it still adds up. Foundations aren’t cheap.