If you haven't ridden a bike before at all I'd suggest that you don't start with a fixie. If you already know how to ride, and want to take up fixie riding, then go for a bike with front + rear brakes and good pedal-to-ground clearance(=short cranks).
craigslist.com
a good cheap beginner bike is Orion 125cc
xr200 a good starting bike cheap and reliable
Yes, this would be a good bike for you if you are 14 years of age. This motorcycle is a dirt bike.
a xr 100
If it truly is a vintage bike - don't. Whatever value it has will disappear when you hack it up. But If you insist: Start with finding out what kind of dropouts you have. Only bikes with (semi) horizontal rear dropouts are good fixie candidates. Next check your rear OLD - Over Locknut Distance. Basically the width of your rear hub, the distance between the rear dropouts. Then go shopping for a fixie rear wheel with the same OLD. Install fixie wheel. Check what your chainline looks like. If you have a double crank, you might get a better (=more parallel with the plane of the frame) If you use the inner chainring. If that doesn't give a tall enough gear you might have to shift the rings around. Or swap to a Single-Speed crankset and a shorter Bottom Bracket. Once happy with that, fit chain and ride.
Bike trainers vary greatly in price and quality. Spin Doctor and Travel Trac make decent good trainers without spending a great deal of money. If you are using your road bike, you should change the rear tire of the bike to either an old tire or a cheap 1 to save wear and tear on the one you have installed.
They can be anything from about 8$ for a cheap one to 15-16 for a good quality one.
dirtbike, for sure. but dont get a crappy trail bike. get a good race bike, even if you dont race
stay in a good hotel cheap but good:)
for a pit bike in good condition a 110cc bike should be expected to hit 60MPH but mine hits 68MPH