I'm actually appalled by the overwhelming preteniousness of some responses here, so I'll help you out.
When I first started playing, I couldn't afford anything more than $100 in my wildest dreams. On a whim I searched on musiciansfriend.com, having used them before, and found a Rogue Dreadnought RA-090. It's seriously an amazing acoustic FOR THE PRICE. I found one on amazon. ($70 free shipping)
It's a perfect starter. The action isn't too high, and you get okay tones out of it. I've had mine for 13 years. Yes, it's not a guitar I play anymore. I've much improved my playing, and have a great salary now. Playing on a guitar that has a little high action has helped build arm muscle. Now when I play nicer guitars, it's much easier.
Today, I have a Gibson SG and a Martin DX-1. Both are the least expensive in their class, but absolutely lovely to play.
You'll get there someday, or you'll decide it's not for you. Getting a cheap acoustic can help with that decision. Don't listen to these guys "dude, don't bother playing anything if you can't afford a guitar over $100". That's just petty pretentious jerk talk.