It's a dangerous job, and unfortunately you aren't going to get paid what you’re worth, but you can make a nice living doing this thing. Assuming you’re actually able to keep safe and have a living, of course.
Starting out, you will probably make somewhere in the $25k-$30k range, maybe $5k-$10k more if you're in an urban area, where the fires are more frequent, the damage more considerable, and the structures more sizable. Most firefighters are paid an hourly rate, and can earn overtime if they are called upon to go over their designated number of hours for the week. After 10 years you may be able to get a few raises and be making more in the $40k-$45k range, but probably not much more than that.
If, however, you have your sights set on getting promoted and overseeing or supervising things in the firehouse, you can get paid anywhere from $50k as a fire lieutenant to over $100k as a fire chief, and that's not including the great pensions or fantastic retirement plans and health benefits. (Although it can be argued that the great health benefits are a bit canceled out by the high risk of becoming injured or sick in the first place.)
When it comes down to it though, you're not doing this for the money. You're doing this because you want to help people. And because you've always wanted to take a ride on a fire truck.
Keep on truckin'.