Bicycles are like anything else - below a certain price, you are just throwing your money away - consider buying a car for under $1000, they exist, but they are probably not going to be sturdy, reliable transportation like you are looking for. Similarly you can go to the other end of the spectrum - it is easy to spend over $50,000 on a car, but is it going to be any more reliable and sturdy than one for 1/10 the price - in my opinion, that is doubtful. In my opinion, the sweet spot for pricing on a commuting bicycle is probably from $500 to $1800 - at the lower end of that is what you will pay for a decent used bike on Craigslist, and then upgrading it with what it needs to turn it into a reliable commuter. At the upper end of the range are things like a Surly Long Haul Trucker (once you add fenders, rack, bags, lights etc).