Pricing is always hell until you decide to be honest with yourself about what you are trying to do.
So I'll ask this question. "Are you really doing this with the hope of making money as a viable business?"
- If no, pricing properly doesn't matter, cover your costs and go have fun.
- If you are trying to build a body of work you can show off as a portfolio, trading your work as a photographer for your "client's" work as a model is a fair trade.
- If you are testing your market to see if your work will sell at a certain price then you can't give it away or all you learn is that it will sell cheaper.
- If you really want a viable business then as I remember, Professional Photographers of America (PPA) says that your "cost-of-goods-sold" should be about 30-40% of your sales price when using film and doing business as a home based studio.
(Side note: For comparison, digital cost-of-goods-sold is about 20-30% PLUS about 10% for depreciation. For film based studios depreciation is only about 1%. So essentially film and digital studios stand on an even cost basis in the real world.)
PPA puts it pretty bluntly too if you ask for their help; if your cost-of-goods-sold is greater than the norms, your business is in trouble and it is not sustainable.
These percentages are real numbers based on the real experience of thousands of photographers over many years.
So you need to figure your real costs and do some math, here's an example.
For my portrait jobs the film goes to Richard Photo Lab. I have them process, color correct, print proofs on 5x5 paper, and put 40mb scans on a disk.
After I add the cost of a roll of film and postage both ways, I figure it's about $35 hard cost per roll on average.
I can't do all that work any cheaper in house unless I give my time away.
So for me, the math is simple, $35 cost divided by 35% (which is my target cost-of-goods-sold) = $100 per roll (135 or 120), and so that's my going rate.
I also charge $100 a flat fee just to show up for an on-site shoot (even if the job is close you'll probably have 1-2 hours in travel, mailing, sorting, and setup time).
Don't sell yourself short.