Your proposed monthly payment x 360 + cash you bring to the table = Approximate cost of the loan
Example: $2,250 x 360 = $810,000 + $25,000 = $835,000
So once the finance company get their cut, you’re total cost is much more than your purchase price of $350,000.
Compromising on quality seems very precarious to me. Be realistic, be objective, and be fair with your home builder during the build process. But also keep in mind that not all home building experiences are gems, and the size of your investment is great. So since this is one of the larger investments you’ll make, treat it as such. Expect quality, craftsmanship, accuracy, and honesty throughout the whole process. If your expectations are not met, or the house isn't right, don’t buy it.