If you have to buy a bike, where and from whom you buy it will be as important as which brand or model you choose.
If you don't know a lot about bikes, you should consider buying a NEW BIKE from a LOCAL BIKE SHOP (also known as an "LBS", or sometimes an Independent Bicycle Dealer). I say this for several reasons, which I'll go over in part (b).
I love used bikes. If up-front cost is your primary limiting factor, a used bike might be just the thing. That said, used bikes are not practical for everyone. More on this later.
Regardless used or new, the following is my best thinking, refined over many years:
- A lot depends of your goals, needs, and desires - think about them realistically.
- Find a local advocacy organization (here). Members get discounts at local stores.
- Don't go bike shopping on a spring weekend expecting hand-and-foot service.
- Never buy a bike from someone you don't like or don't trust.
- Get a big fat lock. Err to the side of caution. The same goes for a helmet.
- You don't need special clothing, shoes, etc. to ride a bike. Accessories like these can make riding easier or more enjoyable. Get them if you want them, but not if you don't.
- Plan ahead: If you don't get a basket, you won't be inclined to use your bike to run errands; If you don't get a light, you won't want to ride at night.
"Bicycles are fun & 
