Leaving aside the issue of credit rating and focusing just on the cost of home ownership, a house costs a lot more than just the mortgage payment. I bought my house for $142K and it had previously been renting for $1300 a month. My property taxes plus homeowner's insurance alone come to $400 a month, so if I had a $900 per month mortgage I'd be at $1300 a month minimum, before considering the cost of maintenance and repairs and upgrades and whatnot.