$185,000 buys the median home in St. Louis right now. With 20% down, that's a $37,000 down payment and a $148,000 loan, set against a $52,000 median household income.
Property taxes in St. Louis run 1.35% of assessed value, above the 1.1% national average. On the median home, that's $2,498 a year, or $208 added to the monthly payment.
Missouri levies a state income tax on top of the $1,249/month this mortgage runs. Model your real after-tax take-home before deciding how much payment you can carry.
St. Louis's cost of living index is 87, below the 100 national baseline. That's on top of the housing numbers above, not instead of them.
St. Louis's median home price runs 27% lower than nearby Kansas City: $255,000 there versus $185,000 here.