It's getting to be that time of year - in a few months, a lot of people will be in the market to buy a new bike. I just read this article, in which the author earnestly attempts to provide guidelines for the purchase of a good used bike from craigslist. While I agree with some of the points made here (don't waste money on el cheapo department store bikes), I have a number of disagreements, too. But picking apart these quibbles one by one would require a long, tiresome essay, and in the end some other knowledgeable person will say, "yeah, but..." And they'll be right!
Shopping for a first-time new or used bike can be daunting. To make an informed decision, a large volume of technical information must be sorted and distilled, and that winnowing process generally takes some level of expertise! The internet forums are full of "expert" opinions that reflect either ignorance or strong personal bias, and it can be difficult for a novice to figure out who in cyberspace knows his/her stuff and whether that info applies at all to one's personal needs. Maybe the prospective new bike person has an expert in his/her life - a coworker, a relative, a friend, etc - but again, as with the internet forums, it's not always easy to know if your personal guru, no matter how knowledgeable he/she seems, has biases that make any sense for you. A common example is a person will come in to a bike shop looking for a new bike for fitness, fair-weather recreation, and/or commuting, having been informed by a coworker who does triathlons and whose chief credential is having purchased a $3000 bike. If that person also wants to buy a $3000 bike for triathlons, then maybe the friend's advice is useful. Even then, one person's experience is a single data point.
I have my own recommendation: trial and error. Yes, in a world of highly technical knowledge and well-reasoned recommendations, a human has to ride the thing, and that's where it gets complicated. My bikes are all excellent, for me. Some other people might like them, too, but most cyclists would prefer something else. At least one local custom framebuilder, reportedly, will not build a bike for a customer unless that customer has enough experience to know what he or she actually wants. The framebuilder is highly regarded for his craftsmanship and technical knowledge, but he knows that his splendid machines will not be well-received if they are somehow inappropriate for the people who ride them.
This doesn't mean that an uninformed person should blindly take a stab at buying a random bike and hoping to learn a few things from it. It just means that it's not reasonable to expect that a first-time bike purchase will result in the perfect bike to last a lifetime (even if the buyer attempts to become informed about tech details). Get one that's good enough, ride it for awhile, and next time you buy, you'll know more. To get one that's good enough, I suggest finding a good bike shop, communicate your desires to them, and rely on their expertise. In the Twin Cities, we have several dozen shops, and certain shops will accommodate the needs of certain customers better than others. It pays to visit several big shops and several small shops and find one where you feel comfortable. If you feel like the 20-year-old salesperson in the funny hat doesn't understand your bike priorities, you're right! Try dealing with another salesperson or another shop. In any case, communication is huge. Clearly describe what you want, and ask lots of questions. By and large, bike shops are not like Target, where the customer is expected to locate and select merchandise from the shelves with little or no input from store staff. In the case of bike shops, good ones at least, talking to the staff will be the most important thing you can do to get a bike that fits your needs.
The next question is how much to spend. If you're rich, spend a lot, if that's what makes you happy. If you're normal and money is an issue, then make sure you inform the salesperson at the bike shop of your approximate price range. There's a high variance in price-tolerance here, so don't assume the salesperson is a mind-reader. Recently a guy told me he wanted a slightly fancier-than-stock Surly LHT, but that he was trying to keep it somewhat economical. When I started throwing out specifications and prices, he corrected me that he was actually looking to spend double what I was quoting! He apparently considered $3000+ to be an economical bike, while others feel that $300 is a princely sum for a bike, and others apparently think the good bikes start at around $8000. Luckily, an entry-level "hybrid" with decent parts, which would be an excellent choice for many first-time cyclists, is around $500 give or take. For those of us who want to ride more regularly, maybe it's worth spending a bit more to get a bike that can be more easily adapted to our needs as we advance our cycling skill and knowledge. The best bang for the buck, in my opinion, is in the range $1000-1500. Most Surly bike models fall into this range. With bigger brands like Trek or Specialized or whatever, this is the price where the road bikes start to be not blatantly cheap. Here's some wisdom:
You don’t need to spend a million dollars to have a great bike, but if you do spend a million dollars and know what you want you’ll probably also have a great bike.
I don't recommend used bikes for inexperienced cyclists, in general. There are simply too many ways to get ripped off, even if the seller is perfectly honest. Some old bikes require parts that are obsolete, and it's too easy to miss costly mechanical issues even for someone who has some experience with bikes. If you happen to be looking at a new bike, and find a used one just like it in nearly new condition, but at a fraction of the new price, it's probably a good deal (unless it's stolen). Otherwise, I'm of the opinion that there are few (if any) deals out there for used bikes. Anything that's a remotely good bike for a remotely good price is likely to be pounced on by those who make a lifestyle of trawling craigslist. For most of us, the extra cost of buying new is a worthwhile sacrifice for professional advice, some kind of warranty, and getting what you want instead of whatever happens to be available used.