1) yeah, i dumped my boyfriend because i found out he was boffing the girl next door. 2) on saturday, my boyfriend goes boffing with his friends. I mean the sport.
A standard professional bike weighs between 14 and 18 pounds. Today most bike frames are made from carbon fiber as are many of the components and wheels. Typical cost is between $6000 and $20,000 USD per bike.
I would say if you are buying a quality dirt bike new it would cost anywhere between 2,000-14,000 dollars. Used would probably be anywhere from 500-9,000 dollars. There are more expensive ones but this is for a quality dirt bike, not an extremely professional dirt bike.