This hits the nail on the head. Bikes/components/accessories are more sustainable purchases, provided Murphy doesn't somehow find you every single day that you bike-commute. Filling up my gas tank is $60/pop, and will last two weeks due to the short drive to work every week (and the fact that I don't go much anywhere else during the week), but even so, $60 on ONE decent bike component will take you many more miles, for a much longer span of time. Just like with cars, one can get carried away with bike purchases, but if you're smart about it, you can wring so much more use out of your money on a bicycle.