Here is some advice for newbies I just heard myself giving yesterday: sometimes, working for free is a good move and sometimes it is not. I did it quite a bit when we started; looking back, some of my greatest clients came as a result of me taking a chance shooting for an ‘opportunity’ instead of money.
There is lots of flash and dazzle in the world, and many people keen on using it to gain free services and favors – often for the very crowd with enough money to spend on decent images! If [when] asked to shoot for ‘no pay’, you should evaluate each opportunity to see if it is legitimate. Ask for the shoot details: what sponsors are involved, what industry vendors are involved, how many guests, VIP’s, and what publications will feature your images, etc.? The answers to those questions will tell you the value of the opportunity to you and your business…or to stay away.
If the sponsors show a consistent appreciation (and investment) in good quality photography, the “new connections” promised will be accessible, the experience is that unbelievable, the exposure is in front of the right crowd (your target audience), or the free food and drink is that good – sure, do it (especially if you are hungry!)
If you are shooting for a client to earn their direct business, only shoot for free ONCE. It should be an opportunity to get your foot in the door and prove you are worth more. Provided you have success on the first shoot and they ask for ‘free’ again, the answer should be a firm ‘no’. They are probably taking advantage and may not value you or your photography!
On the other hand, if you are shooting for free to gain respect, photo credit, awareness of your business, or exposure – only you can be the judge of how many times you snap for free. Did you meet people the first time? Did you get comments or feedback from people with whom you would like to develop relationships? If it was a positive experience with positive outcome for you and your business, go for it!
When it comes to money and the ‘free’ has passed, start the fee structure where you are comfortable providing the level of service and quality value required. Translation: don’t charge $200/hr if you can only provide $25/hr worth of quality and service! Be real – do you have the equipment and the experience to get top $$? Similarly, don’t forget about your post-production work. You are not just charging for your time on the shoot – there are hours on the backend to consider, delivery time and/or fees, expenses like gas, parking and food, clothing for the event attire requirements, and the list goes on.
I hope this helps a little…maybe there will be a book later 
Only thing I can promise, what I don’t cover here will be addressed with your future experience!! Now, go forth and shoot!!!
