Too many times, I've seen folks go on an interview in jeans or looking like they're going to hit the club afterwards. Even if you are applying to be a trash truck driver, you should still dress professionally. And I don't want to hear "maybe they can't afford a suit" because that is bull. If you can afford a pair of jeans or club clothes you can afford to buy something presentable for an interview. I have three suits in my closet specific for interviews and I did not pay more than $50 for them. One my mother found in TJMaxx for $4 (yes you read that correct FOUR dollars.)
There are programs that sell gently worn work clothes at thrift store prices. One program I know of first hand is Dress for Success. They sell professional attire and accessories for the LOW.
When I have some free time, I'm going to create a few interview looks for women and men. I will also give a couple of interview tips like saying YES and NO instead of yeah, naw and the one I hate the most HUH.