The economy seems to be coming back a bit and so your photo business opportunities should be, also.
One mistake people tend to make when offering services is to understand where you bottom really is.
Negotiating is fine and more people are becoming accustomed to that these days.

But don’t let it get this far:

That scene is from a 60’s movie called Putney Swope about the world of advertising on Madison Avenue. Directed by Robert Downey, SR. Yep, Iron Man’s dad.
As the Mad Men era was drawing to a close, this movie put an outrageous spin on what was happening in the world of advertising. Not one for the kids, but very funny stuff.

Any way, the point is that when you negotiate your prices, you must have all of your costs and options at your fingertips.
Do you use a rate card?
If the photos are being used in advertising, where will they be used and for how long?
Is the exposure you will get the main key? Sometimes the association with a client may bring in more work.
What are your hard costs? Those numbers won’t lie and you can donate your time, up to a point. Shooting 5000 exposures will take some editing time and some post work at least for presentation purposes.
Figure out how your gear costs are amortized, at least over the course of a year, and how many gigs it will take to cover those costs.
There are so many parts of the photo business and so many ways to charge.
True, the current economy and ability to get a passable image with the gear available has changed the marketplace, but remember your working brothers and sisters: don;t give it up for free, like Mark Focus.
Look what happened to him.