Art is a luxury. Skill and experience are required in order to create high quality art. In the state where I live, the minimum wage is $12/hour (Salary.com, 2023). I believe that my art is deserving of more than minimum wage, so I charge more.
For traditional art, the cost of canvas and paints add to the cost of a piece. In addition to the time it takes to complete working on the piece, the skill and years (in my case) of practice add to the price.
For digital art, pricing is a bit different. Prices for digital pieces are based solely on how long it takes me to complete a piece on average.