The moment you lose focus on your bank account, you lose focus on your work.
Ah, I'm not making much on this, it's just to build my portfolio.
I can't seem to get ahead, maybe I need different work in my portfolio.
Crap, my car just broke down, there's money I don't really have or want to spend on repairs.
Car payments, insurance, gas, tires, I hope it all lasts till I have my portfolio stuffed full.
You like to take photographs! Outstanding. You want to continue taking photographs?
Where is the motivation? If you intend to make money at it when you get there, when will you be there?
Photography is Your Goal. Kewl
No money, No photography. No Money, No Photography.
???
Without money there is no camera, without camera there is no photograph.
But I just do it as a hobby. Kewl. Do you always give people your money as a hobby, cause if you do I wana come stand in the line.
??? 
Where you work for money, when you break down what they pay you by the hour?
You drive to work, how much does it cost you to drive there and back?
??? Car payment, Insurance, Gas, Wear and Repair per month < X amount of money.
Take X amount and divide, days in month you work at your day job. There's how much it costs you to drive to work each day. No you say, well you work to pay for the car, so yes!
How much do you make per hour when you break it down that way. Y amount of money.
--
Now you have a shoot to drive to.
Drive time, plust shoot time, process time- now you have how much time involved.
You know how much that days car expenses are, no you say. Well it cost yuo to drive to your day job. What the difference,, day job, night job ( hobby )
Ok so now we know how much for time and vehicle expence. XY
How much for the CD or Prints? Ok now you can add that in. XYY
X + Y + Y ='s how much it cost's you to just show up and shoot
Now you add in the cost of your equipment, repairs, insurance... It goes on till you list all that is involved and a cost on it, what it cost divided by how many uses you expect out of it.
If it is a hobby are you at least breaking even? If not the only person cheated is you.
This is just a pinch of how to go about figuring cost and then there's the markup, the money you can bank or spend, or reinvest in more gear.
Money may not be the goal but, lose site of it and you can't afford to reach that goal, your work will become humdrum, done every now and then.
Where's the Prize?