Snowboard because its better than a dirt bike.
Buy a USED 250 dirt bike.
For a 2-stroke dirt bike all you have to do is, buy a taller cylinder, and buy a longer crankshaft.
Not usually. Some dealers will give you a helmet when you buy a bike, but nothing else.
you could buy a cheap second hand bike, or a Chinese mini dirt bike for no more than £600. but if you go for quality Japanese bikes you will pay a little over £1000. http://www.dirtbikefanatic.com/cheap-dirt-bikes.HTML
One can buy a mini dirt bike from the local bike stores. Sometimes local community auctions also feature variety of mini dirt bikes for very reasonable price.
Auto Zone
you don't!!
Ebay, Craigslist, a dealership
for 370 its hard to find a good dj bike. your best bet is to look for one used cuz unless you have a least 700 dollars your not gonna get quality bike.
buy a Giovanni kit bike and follow the instructions
50cc dirt bike may be available at a bike specialist store, but very unlikely. Most 50cc dirt bike are seen online for purchase only. For example eBay and Amazon.