1991 Chevy Silverado Pulls Sharply To The Right

I just bought a truck from an auction. My truck passed the state inspection with no issues. I was driving it and had to make a sudden stop. My truck pulled abruptly to the right whenever you hit the brakes suddently or hard.

The front end has been aligned. The tires show no abnormal wear. If the brakes passed a state inspection, what is causing my truck to pull sharply to the right whenever I suddenly hit the brakes and what is an average cost range to correct the problem?