Believe it or not, I've found that verbal praise is the BEST positive reinforcement out there (and it even fits into my budget LOL). It is amazing what the kids will do just to hear you say "Great job!", or "Nice work", or "That's so creative!"
What you say to the students should be what drives them to succeed. If you have to bribe them to get them working, they won't recall much of what's taught.
I suggest, rather than fret about this topic, you go to [url]http://teachers.net/wong/JUN04/[/url] and browse the info from "Harry and Rosemary Wong". These amazing educators have written a book called "The First Days of School" and was an absolute LIFESAVER for me last year, as I also entered the profession.
An article of particular interest on the above mentioned site is called "A Well-Oiled Learning Machine". Check it out and best of luck on your first year!