$32 Suit Jacket.
$10 Black Pants
$7 Collared Shirt.
$0.97 Shipping in the US.
http://www.walmart.com/ip/George-Men-s-Suit-Jacket/13279256.
Unfortunately it's Indonesian Sweatshop Labor, but it works. If its all you can afford, then.... $50 for a complete suit.
Even from that picture (which is naturally one of the best representatives of the product line) it's going to be cut like shit and look bad on almost any wearer. You'll look like a goof. Would work for an engineer, if his interviewers were likewise engineers, but for any other professional position--$300 or so is an investment. (And $300 is astonishingly cheap for a decent suit: my better suit was $500, bespoke, my other one was a $350 off-the-rack separates and I could have gone cheaper but I liked the cut of this one better.) A bad suit is worse than no suit at all, because it looks like you don't know how to dress yourself.
'Course, you could also just target employers with a more casual dress policy. For my current position (decent software engineer position, not making millions but doing alright) I came into my interview wearing a button-up shirt and a nice tie; by the time I was talking to the second interviewer, 45 minutes in, I'd ditched the tie and unbuttoned the top button of my shirt because none of the people I was talking to cared how I was dressed.
If this guy is really broke it might be his only option. If he doesn't have it to invest, then what?
I have a $500 Italian suit (Grandfather's in surprisingly good condition, was valued in his estate when he passed on...); bought this one. They look almost the same. The expensive one has pinstripes and has a slightly narrower cut, but that's it. I work for an attorney. No one in any court we go to has ever said anything bad about it. So whatever.
If you don't like that, check out the double breasted:
http://cgi.ebay.com/J-CREW-Mens-PURE-WOOL-Sport-Suit-Coat-sz-42-R_W0QQitemZ150560419491QQcategoryZ3002QQcmdZViewItemQQ_trksidZp4340.m263QQ_trkparmsZalgo%3DSIC%26its%3DI%252BC%26itu%3DMRU-11450%252BUCI%252BIA%252BUA%252BFICS%252BUFI%26otn%3D10%26pmod%3D160506897103%26ps%3D63%26clkid%3D7462384817318508710Look, the most important thing is to keep your chin up man. You ain't wearin' an expensive suit? Pretend you are. Everyone puts on pants one leg at a time, no matter how much those pants cost.