Robert, this is a tough one, as Neal has already mentioned. There are a few things that have not been mentioned that you need to factor into your pricing, especially if you are harvesting your own wood. If you are buying your wood, then you already have the cost to acquire it. But if you are going out to "hunt for it", then things get a little harder to quantify.
I harvest almost all of the wood I use. Sometimes it is easier, sometimes it is harder. But, I need to consider my time in obtaining that wood and getting it home, as well as the cost to buy and maintain things like my truck, saws, and other handling equipment. Other handling equipment means things like my 16' flatbed trailer, my Harbor Freight lift gate, etc. Free wood is not always cheap!
And even while most of the wood I get I get for what amounts to sweat equity, I need to think about keeping my wood finders happy, so I need to factor in the occasional gift back to the tree people who think kindly of me when they find burls or unusual wood. I recently obtained an English white oak burl that cost a little more than usual, not for me, but for my tree guy. He ended up burying his saw in the ground to get to the burl, and it took him time to fix the chain. He did not pass that on to me, but you can believe he is going to get a "bonus" piece from me because of it!
I also need to factor in what it might cost me if I actually had to buy this stuff. And that makes things even tougher sometimes, but it needs to be done. I can get a burl dropped off in my field (like I did this past Tuesday), but if I had to buy one of a similar size, it would cost quite a bit of money. I have a good supply of this stuff right now, but that is not a guaranteed source, and the day may come when I have to buy it. I can't jump my prices to reflect that change all at once. And, on rare occasions, I do buy wood, and I try to keep the prices of finished pieces from that stuff in line with the stuff I find alongside the road.
The one big paradox in all this is time. Ironically, the better you get at this stuff, the faster you can go, but the more you can charge for any given piece. Then someone wants to know how long it took you to make it. Answers to this question need to be contextually sensitive. If I am discussing a technical point with other turners, I try to be as specific as possible. If I am discussing it with a customer who I can tell is trying to use the time factor as a gauge of how much the piece is really worth, then I need to be a little more vague. For those people I talk about how much effort and work goes into getting the log home, processed, how much waste can happen, and then I go into a little bit about how much equipment is involved, as well as how long it took me to develop the skill to even dare to tackle this particular piece of wood.
All of this is true, just dressed up a little for consumption by the proper crowd. But if I am telling someone they should buy a bowl from me for $200 and it only took me an hour to turn it, they are going to walk away in disgust, no matter how much they liked it. And it does not matter how much other stuff went into getting that bowl finished, they are going to hear "one hour".
Then there are the people who say you should never reduce a price or bargain with a customer. I will not haggle with people, and there are times I will send someone packing if I don't like them or their manner, but I also have enough margin built into my prices that if someone is wavering, I will make them a deal. Sometimes someone cannot make up their mind as to which piece they should buy. Often they want two pieces, but will walk away with none if they cannot resolve the problem on their own. I have been known to offer a token discount if they take both, or sometimes three or four! Since most of my sales are direct, this discount never amounts to any more than it would cost me to have a gallery or gift shop represent my work, but at the same time I make a sale and the customer goes home happy. But the people who show up to haggle like it is a flea market go away empty handed or at full retail.
Check out what others are getting (not asking) for their work, and see how yours compares to theirs for quality of wood, finish, etc. It is not always easy to get prices, but if you see someone moving a lot of stuff, that is an indication that their prices are at least acceptable to that person. They might be low, but that is their problem. But if you see heavy bottomed oak bowls sitting for months because they are $500 each, then you know someone has an unrealistic view of his own work. (I saw this in one gift shop. I had burl bowls priced the same or below a guy who was selling poorly done red oak bowls. And they wondered why his stuff was not moving! Mine was not the stuff out of line either.)
Sometimes your own personality is a factor. There are people who can make beautiful stuff, but should not be let out in public. They do not sell as well as someone of lesser skill but with greater people skills. We are selling luxury items here, and people need to know how or why owning your piece of wood is going to improve their own life. There is a whole host of reasons for this, and each person is different. Learning how to interact with people on this level is going to get you higher prices. If you can connect with people, tell them a story about the wood, or show them why they are going to be a hero for bringing home a piece of yours, it is going to put money in your pocket.
As others have mentioned, location is important, and there are a host of other variables. But we are not like contractors who can give a price per square foot as a gauge for their work, and then hope to make money. Charging for your work is as much of an art as the work itself. Good luck with it!