It's worth what people will pay, or what the artists feels he is happy to take in compensation for losing his work.
As a student I did alot of 30 second life drawing sketches of a woman slowly getting undressed in a roughly 6x8 inch sketchbook. When I moved to the US I ripped out a page and coloured it with some acrylics and had it framed and hung up in a permenant exhibition at a local gallery. It was one of the pieces that sold for $400 and took me about 2 minutes to make and $40 to frame.
I didn't expect anyone to buy it, and didn't really want people buying my paintings so I had quite a high markup, but people still bought 3 of the 12 I had up and I made almost $3000
So at the end of the day its worth what it's worth.
As a student I did alot of 30 second life drawing sketches of a woman slowly getting undressed in a roughly 6x8 inch sketchbook. When I moved to the US I ripped out a page and coloured it with some acrylics and had it framed and hung up in a permenant exhibition at a local gallery. It was one of the pieces that sold for $400 and took me about 2 minutes to make and $40 to frame.
I didn't expect anyone to buy it, and didn't really want people buying my paintings so I had quite a high markup, but people still bought 3 of the 12 I had up and I made almost $3000
So at the end of the day its worth what it's worth.