What kind of bike should I buy?

yeah, check craigslist for a used hybrid cuz non-big chain bikes generally start at about $300. Hybrids and comfort bikes have a more upright position so less strain on your neck and back but comfort bikes have wider tires like a mountain bike which is great if your on gravel but slower if your on paved road. hybrids have a skinnier tire than the comfort/mountain bike but wider than racing style"10 speeds" and also they are a larger diameter making each pedal count more.Also make sure it fits, as in the frame size, seat, etc or thats gonna be the longest, most uncomfortable ride of your life!