The Reliable (or Not) Garage Bike  
The first thing you need to do is find a bike, if you don't already have one. The most inexpensive answer for this is the "garage bike," which is the one way back in the corner of your garage which you haven't ridden or even seen in years. Another is someone else's garage bike, if you can talk them out of it. You can also scour the neighborhood for garage sales, many of which have very adequate bikes for very little money. Just clean it up and fill the tires. For this you'll need a floor pump with a pressure gauge and you'll need to know the recommended pressure for the tires you're filling - this is usually found embossed on the sidewall of the tire itself. After you've spiffed it up, give it a spin - if it feels OK, you're good to go!
Buy Used  
On the other hand, garage bikes are often rusty and damaged and may require some wrenching to meet your needs. They also usually don't have the newer technology (not to mention the cachet) of today's sporty bikes. So if you're aiming higher in your riding expectations, or just want to look cooler, you can find good used bikes everywhere.
Online Sites  Check out eBay or Craigslist online. You can find good late model bikes from $50 to $5000, depending on the make and model. The process is quite safe and you can find some very good deals if you're patient. You can look for something within driving distance and pick it up to avoid shipping charges. There are also many biking forums which offer classified ads. If you know exactly what you want, you can Google it and get all of the above.
Newpaper Ads  You can also check out the classified ads in The Blade or neighborhood papers like the Sylvania Sentinal or Maumee Herald.
Buy New  
Of course, you can buy a new one. If you've done your research and know exactly what you want, you can buy direct from many manufacturers. On the other hand, your local bike shops will have a variety of makes and models (though limited) and can help you choose the best bike for your needs. They can also fit it to your body and supply you with all the bells and whistles you want - and, after all, what's a bike without those bells and whistles? It's generally not a good idea to buy from department stores or big box sporting equipment stores - they are likely to carry mostly low-end bikes and won't have the expertise or willingness to provide service after the sale.
Not Your Father's Bicycle  
If you're going to spend significant money on a bike, new or used, you'd better have a good look at the variety of bikes out there these days - there are more styles than you can imagine! Each style suits a particular type of riding and has its own significant benefits. You should keep in mind exactly what kind of riding you want to do and select a bike accordingly (here's where a local bike shop can be of great help). You might start out with a relatively inexpensive bike which will be good for a wider range of riding rather than spend big bucks right away on a specialty racing or touring bike. You can always upgrade later when you discover your real riding passion. Here's a partial selection of bikes you might want to consider.
Fit the Bike to Your Need 
What kind of riding do you want to do? If you know, select a few categories of bike that seem suited to your needs and test ride some bikes. The most important thing is that the bike feel good to you. Of course, if you're test riding a touring bike, what feels good on a neighborhood ride might not feel as good after 50 miles of touring. Again, here's where a local bike store can help with good advice. If you don't know, the best advice is probably to buy a cheap bike to get started and save for the one you'll really want when you know what kind of riding you want to do.
Fit the Bike to Your Body
Before you buy a bike, adjust it for your body to make sure it's comfortable. Different bikes will have different kinds of adjustments you can make, but there are two adjustments you can (and should) make on any bike.
Seat Height 
The seat (or saddle) adjusts upward and downward to accommodate the length of your legs (you'll probably need a hex, or Allen wrench, to adjust the seat). The seat should be high enough that you can completely extend your leg straight downward, with your foot flat on the pedal, for the most comfortable and efficient pedaling. This may seem awkward at first, but you'll soon get used to it. Every day I see people sitting too low, pedaling in a crouch, which is very uncomfortable and inefficient. The saddle also adjusts on the post, with the nose of the seat moving up or down.
Handle Bars 
Handle bars should be high enough to be 1) comfortable and 2) efficient for the kind of riding you want to do. These two things are not necessarily compatible. For example, it's more ergonomic to sit in a "natural" upright position, and that works for cruising the neighborhood; but if you want to ride fast on a road bike, this position is highly inefficient aerodynamically and will slow you down. In that case, lower bars will put your body in an efficient position for speed at a cost of comfort. Try several positions to see which is good for you.
Helpful Resources 
If you want to go beyond these very basic steps in selecting a bike, check out the following online resources - there's more information out there than you can ever imagine. Good luck in your quest!

Bicycle Manufacturers On-Line Biking Blogs General Interest Bike Sites

On-line Bike Forums Local Bike Shops On-Line Bike Retailers

Selecting A Bike Fitting A Bike to Your Body

©2010/2011 Bob Beach