This is a frequent question! And what a complex issue. I'll make it simple. There are two popular ways to determine art pricing. The first is by Square linear inch or centimeters, the next by an hourly rate. Hourly rates are like other labor costs but for artists it is a question of how many hours went into a piece and the "skill level" of the artist.
With linear pricing it's straight forward. For example, a ten inch by 10-inch painting at $1 per square inch is equal to $100.00. As an artist develops an audience for his or her work so to the pricing. One dollar a square inch is considered a base student rate. I have been practicing for many years but still only charge $2.00 a square inch. Keeping prices at a low level for extended periods is not rational as all artists progress in their practice. Keeping prices down is not something sustainable. However, neither is wildly increasing prices so that few but would consider collecting your work. It's an uncertain art (pun) to price art.
For me, the square linear inch pricing method is a solid foundation for artists not signed with a Gallery. Gallery pricing is complicated, and the commissions often are exceedingly high (50% is common).
So, there you have it. But pricing is not necessarily indicative of an artist's true worth and a topic artist endlessly discuss amongst themselves. Artists do talk about their work and the great masters, but they are more likely to ask each other about their sales!
Are you an artist? What method do you use? Please feel free to comment!