If the car pulls to one side when you let go of the steering wheel is the biggie. the more it pulls, the worse off it is. a couple other is you might have shakes, and pulling while driving. and also, over time, one side tire will wear more then the other.
to fix it, the first is to get a front end alignment done. that will run you about $80 or so to do. And that will fix most alignment problems.
if it is more severe and the above alignment doesn't fix it you might need to take it to a specialty wheel and axle place and that will cost more.



