I didn't learn from books. In order to start, you can just do cheap mockups of clothes in muslin (really cheap fabric), but I expect for many people it's worth it to pay for nice fabric and actually make something useable. (Still, use muslin to try out a new technique). The most expensive thing is the sewing machine, which is why you want to learn from someone (and borrow time on their machine) while you work out if you'd use one of your own.

Most fabric stores (Joanne's etc) offer project based sewing classes on site. You can also try Craigslist.