Cheap - I am assuming Value.
Remus - top choice I think $1400 average price for a TUV approved Austrian 303 stainless steel exhaust - I think its awesome
RD Sport -italian made , Stainless Steel and complete exhaust system.
Corsa - good value but I like the way the first two sound.
Those are my top choices for exhausts of great value that sound amazing, let us know we carry all the ones listed in the thread, actualy I think we carry every single brand of exhaust for our BMW's