On the first issue - determining the price of a painting:
When I first started painting, I felt lucky to be able to give my paintings away to someone who actually wanted them. Later, when I couldn't keep up with the demand, I did what a lot of artists do - looked around my locality, at work that was similar to mine, by artists at the same stage I was, and priced my work in the same range. This is not an exact science, so there was some pricing inconsistency in those days. But then, my work was somewhat inconsistent, too.
After I started painting full time my work got better, and more consistent, and there was a lot more of it. I like to organize and simplify the uninteresting parts of my life so that I can spend more time with the good stuff. It was time for a system. Luckily, I had a modest track record of sales at that point, so I pulled out my sales records and figured out the average price per square inch of all the paintings that had sold in the previous two years. I decided that was my current price.
For the next show, I used the square inch formula to price my work, and immediately had to amend it. Anyone who's used this system soon realizes that really small works go too cheaply (a 9"x 12" painting takes almost as much time as a 12" x 18" painting.) And very large works can be too expensive... it depends. So I came up with a three -tiered system of per-square-inch prices for small, medium and large paintings. Each January I raised the prices 10%.
That system worked great for a few years. Then I encountered the changing-collector-base problem. It's a good problem to have, but I didn't know about it, wasn't prepared for it, and couldn't figure out what was wrong for awhile. Here's what happens:
Let's say you're selling work in the under-$2000 range. You have a core group of loyal collectors who have bought a few pieces, tell their friends about you, the friends buy your work, and so forth. But as your prices go up, some of them can't afford you anymore. Sales go down. You can stop raising your prices and continue making sales at that level, or... You need new collectors from the next tier - people who buy in the $2000 to $10,000 range. It can mean looking for different sales venues. Most artists need a dealer to get beyond that level.
Now the prices of my paintings are being set with input from dealers. They all keep telling me the same thing - "you need to raise your prices." But a huge jump (50% or more) all at once just doesn't feel honest to me. So I'm raising them 20% or 30% with each show. Since I have a few shows coming up at the end of this year and next year, I'll soon be entering uncharted territory, price-wise, so I'm hoping for good advice along the way.
Here's another thing I learned the hard way: to have a "rock-bottom" price. That's the price that I never go below (for a painting on canvas) no matter how small the piece is, or how simple it appears, or any other qualifiers. My reason has to do with my style of painting and may not apply to other artists. I tend to paint in a careful, detailed manner, filling the picture plane with approximately the same amount of information, using smaller brushes on smaller canvases and bigger brushes on bigger canvases. So smaller paintings are not necessarily easier, or quicker, and the difference in materials is negligible.
On the second issue - posting the prices on the web site:
At first, I didn't post prices on my web site, because I'd heard that galleries didn't like that practice and I wanted to get into a gallery. But since I was selling most of my work myself, I ended up wasting a lot of time in back and forth correspondence with people who couldn't afford or didn't want to spend anything close to what I was asking. So to cut down on the pointless inquiries, I started posting my prices. Later, after I was showing in galleries, I was asked to take my prices off the site, so I did. The trade-off is that now I can just refer most inquiries to a dealer and let them handle it.
For the curious - my current prices range from $300 to $6,000, depending mostly on size. I usually work in the 12" x 16" to 24" x 36" range. Rarely I'll go up to 40" x 50" or down to 8" x 10".