Where to Buy a New Bike
The best places for a beginner to purchase a new bicycle is either a local bike shop or a quality sporting goods retailer. The main reasons for this is because these two retailers can provide a showroom of inventory, quality assembly, expert recommendations, and test rides. Ideally, they will have experienced cyclists on staff with years of expertise and product knowledge.
Local Bike Shops
If you are fortunate, your community has several local bike shops. If that is the case, it pays to visit several as they often have very different unique qualities. The larger more established ones will have a good selection of brands, models and price points as well a repair department. A shop with a good selection should have 100 or more assembled bikes on display and at least that many in back stock. Most shops are small businesses, often family run. Some will have a family bicycle oriented inventory stock with bikes for the whole family. Some shops will tend to cater to a particular type of bike enthusiast such as competitive racing cyclists, mountain bikers, commuters, or touring.
How to spot a good local bike shop:
Independent local bike shops are like any other business, there are quality, customer focused stores with excellent merchandise, knowledgeable and helpful employees, skilled mechanics, and professional business practices. There are also bike shops run by people who probably couldn't get a job anywhere else and have no idea how to take good care of their store or their customers and don't really care.
Some things to look for are clean, well stocked, well lit stores with attractive signage, prices clearly marked on all merchandise, and well dressed (clean), professional employees. Have a look at the displays, are they neat and organized into departments? Are there areas where the inventory looks dusty or dated with faded or damaged packaging? Look at the repair department. Is it organized and clean? Are customers bikes organized neatly or are they piled and leaning on each other in a way that the paint or components can be scratched or damaged?
Walk around the store and squeeze a few tires, are they inflated or flat? Bikes on the showroom floor should have well inflated tires. Low or flat tires shows a lack of attention to detail. Squeeze the handbrakes on several bikes. Well adjusted brakes will squeeze a short distance before clamping down on the wheel. Both front and rear brakes should have been adjusted to squeeze the same distance. A brake lever that can be squeezed nearly all the way to the handlebar before touching the rim is a sign of poor quality assembly. Take a look at the seats on the bikes, they should be nearly level with the floor. Are there any that are pointed markedly upwards or downwards? if you can, spin a wheel or two and see if the wheel looks wobbly or rubs the brakes as it spins. These problems can be a sign of poor quality mechanics and workmanship at the shop.
Sporting Goods Retailers
Sporting Goods Retailers run by national chains can be a good place to buy a new bike. With their corporate buying and marketing power they can have top brands and good pricing on current models. However the bike department will only be as good as the manager running it wants it to be. Those managers are often in charge of many areas and may not have the time or expertise to run a top bike shop department. In past years, stores like REI, Dick's Sporting Goods, and Sports Authority have gotten much better at addressing the needs of cost and quality conscious consumers. They often have dedicated bike departments with fairly knowledgeable staff and complete service departments.
What to Look for at a Sporting Goods Retailer
Try to find an employee who is actually a local cycling enthusiast. Ask them where the best places to ride are. Ask them how often they ride and what kind of bikes they own. Ask them how many pairs of gloves they have and what kinds of helmets they recommend. You are looking for enthusiastic, detailed answers to demontrate that they have some real knowledge and authority on the subject. Ask them if they know how to install a bike rack on a car. Bike shop employees and bike enthusiasts will able to say "yes" easily. A sporting goods retailer employee may not have ever done this for a customer and may not have done this for themselves. Ask them if they know how to fix a flat tire with a patch kit. If they say yes to this, you likely have found a real cycling enthusiast disguised as an ordinary sporting goods retailer employee.
When you shop for a bike, you need to be properly fitted and you should always take a test ride. See if you can get an employee to properly size you on a bike, adjust the seat and handlebars as needed, and fill up the tires before you take a quick spin to see how the bike feels and performs.
After sales service will be important. Every new bike has a break in period that takes place during the first few rides. The brake and gear cables may stretch a bit, the nuts and bolts may loosen a bit, and the seat and handlebars may need slight adjustments after those first few miles. Ask about after the sale free maintenance or tuneups to get those things taken care of. A good sporting goods retailer will anticipate those needs and provide them to you as a normal part of doing business much as a local bike shop would.
Where NOT to Buy a new Bike
Mass merchant "mart" stores are primarily purveryors of bicycles that can be manufactured and sold at the lowest possible prices. These bikes are the .99 cent burgers of the bike world. There will be no steaks or chefs found there. No one will be there to help you choose the proper size or compare one bike to another. The person assembling it will not be a bike specialist, they might be the person who assembles barbecues one day and do it yourself furniture the next. However, mass merchants can be an OK place to buy a simple, low cost child's bike that will do it's job well enough until it is quickly outgrown.