When interest rates were at historical norms (5-7%), 3x income was a good rule of thumb to estimate a housing payment of 1/3rd your after tax salary.

$100,000/yr = $8,300/month pre-tax = $6,000 after tax

$300,000 home minus $60,000 down @6% = $2,000/month for mortgage + tax + insurance

But I recall right before the 2007 crash my manager was shopping for a mortgage and they were willing to lend him $800,000 on a $120,000/yr salary.