Yes, use transport..
Transports works mostly correctly in Brussels. It sometimes late, sometimes (most of the time) dirty and unpleasant. But it will get you almost everywhere in Brussels. It's still expensive compared to other cities (around 500€ a year if I remember correctly).
If you do not intend to go often out of Brussels, don't even think about buying a car, you'll eat your wheel in no times. Traffic jams and road works are daily routines here. And parking is paying almost everywhere now.