The bikes tested cost from about $300.00 to nearly $2,000.00. It was found that more money buys a lightweight frame made of carbon fiber, aluminum (or a combination of both materials), or high-strength steel and other high-quality components. But you can still buy a good bike for just a few hundred dollars.
Decide what kind of riding you’ll do
That will narrow your choice to one of the four basic types. If your an avid cyclist, you may prefer a convention road bike. Looking for leisurely ride on flat, paved roads? A comfort bike may be more your speed. If rugged trails are in your sights, then a mountain bike might be best.
Find a good bike shop
You’ll pay more, but we think your more likely to be satisfied. Bikes from big-box stores might not be properly assembled or well matched to your body. If you don’t like the pedals or seat on a particular model, some bike shops will swap components at little or no cost.
Take a test ride
Before you buy a bike, ride it far enough to make sure that the brakes and shifters are easy to use, the fit is comfortable, the gears can go low enough for climbing hills, and the frame and suspension adequately smooth the bumps.
Avoid cheap bikes
Inexpensive bikes – those selling for less that about $200.00, often in big-box stores – may seem like good deals, but it is advised to spend $300.00 or more, if your budget allows. Why? Because you’ll get a lot more bike for your buck
Mass-market bikes have cheaper construction than higher-priced bikes and can weigh seven or eight pounds more. They come in only one size, so you’re not likely to get a great fit. And mass merchants can’t match bike shops for quality of assembly, expert advice, and service.
Consider these extras
A good bike helmet is essential. Special cycling shoes and cleats can ease your pedaling. Gloves will absorb vibrations and help to protect your hands in a spill. Polycarbonate glasses can shield your eyes from bugs and errant pebbles. A water bottle is handy to have on long, hot-weather rides
This is from the Consumer Reporting Guide