Originally Posted by TiHabanero

A flat kit includes a spare tube, patch kit, tire levers and an inflation device. All of these items can be had from a local bike store for not much outlay. A bag will be needed as well, one that mounts under the seat is my preference. Get one that not only fits the flat kit, but has room for a energy bar and perhaps a small phone. Too large of a bag becomes an annoyance, too small and it becomes a hindrance.

One mention on inflation devices. C02 is great, but after using it for a year I went back to a good ol' frame pump. Costs nothing to use, and never runs out of air after multiple flats. The Topeak road morph for a road bike and the mountain morph for a mountain bike are my favorites. Mini pumps simply suck. Been there all day pumping and don't want to do it again. The Topeak will take you to 100+ psi without much trouble and does it in a reasonable time. Mounts under a water bottle cage.