Someone with basic mechanical knowledge can buy a bike off CL, some grease, and some BB's and be up and running for under 100, you can also go to walmart and buy a BSO that will function for under 100 dollars, often bikes are inherited from friends or family for free and you can get them a tuneup at a bikeshop for under 100 bucks.. conversely you could also walk into say a performance shop and spend 10k on the bike alone and another 10k on "gear" cycling is dirt cheap compared to cars and the gap merely widens at the higher end how many multi million dollar bikes have you heard of?