Have you ever bought a car?
Lets say a jeep grand cherokee, cloth seats, no nav, no sun roof, v-6 $30,000
Now you want the grand cherokee with leather, nav, sun roof, v-6
Now you want the grand cheokee Limited v-8 $42,000
Now you decide you want the grand cherokee overland package
Now you decide you want the grand cherokee SRT $64,000
Same goes for a house, from choice of windows, siding, kitchens, baths, lighting fixtures, appliances, contractors, architects.
So as you can see its based on your tastes, expectations and pocketbook.