Jon, where are you planning to sell them? That will have a lot of bearing on the price. If you're selling at local art or craft shows, what are similar pieces selling for at those venues? That's often a decent starting point. I've been adjusting my prices since I started doing shows last year. I started out with things priced on the high end of what I thought they might sell for, but after seeing people pick them up, look at the price, then walk away, I started lowering my prices a little bit at a time, until I found the range at which they'd sell.
For a starting point, some people use a size-based pricing system, say $10 per inch of diameter, plus another $10 per inch of height. In this case, an 8" x 3" bowl would be priced at $110. In different markets, the "per inch" price would need to be adjusted. Also, there can be a premium added for particularly nice pieces of wood, or anything else than makes the piece special.
You have to be realistic about what the market will bear. I went to a show in my neighborhood recently (as a customer, not a vendor) and met a turner working his first show. He had apparently been seeing the prices that the "name" turners in the AAW can get for their pieces, and figured that was what he should be charging. I didn't have the heart to tell him nobody in our neighborhood was going to pay $350 for a 6" x 1 1/2" bowl. It was a nice enough bowl, but he'd be fortunate to get $50 for it here.
If you're primarily selling by word-of-mouth to friends and family, it gets a bit trickier. People will tell you that your prices are either under or over what they should be. In my experience, a few of my friends and family say my prices are a bit low, or are about right...the remainder of them can't afford to buy my work.
Another factor (for me, at least) is how much want to get rid of the piece. I'll sell something I'm not real fond of for much less than some of my favorite pieces.