1) People that listen to music like 50 cent, are most likely to wear cheap tracksuits and fake burberry from the local market, they think they are hard and they are covered in fake jewellry, or 'bling' as they call it. The usually try to put on a false cockney accent but they seem to have their own kinda slang.
2) It's sometime something people are called when others disagree with their clothes or taste in music. It's sometimes used as a childish insult.
3) Almost the exact opposite to a goth!
"Ye, giz a fag."
"Nah, yeh don't want these, they're dead rammeh"
"I guess it's back to Coke then..."