I think they're cute as fuck. If they're a neutral or dark, they won't look cheap. I've even seen dark red/burgundy and I think that looks really good too. The only ones that look cheap are the American apparel ones in my opinion, like the ones that have the stripes on them.
Pretty much every guy I know finds this look to be incredibly hot if the person can pull it off. It can be dressed up or dressed down to look hot, chic, cute, playful. Super versatile, and super attractive.