Yeah I remember currency when he was on waynes shit almost every mixtape. He was alright, I didn't think he was that great though. Check out Joe Budden, he's underrated and has some good lyrics. Not like wayne or currency though, his style is different.
I recommend downloading Mood Muzik 2 & 3 if you like him. Listen to one of his freestyles
http://www.youtube.com/watch?v=1Wv2A89a5_g