My current prices are as follows, subject to change, but I will never change a quote after accepting a deposit, dependent on materials availability:
8"X8" panel: $125 Single, simple subject with no intricate details.
10"X10" panel: $165 Subject with no intricate details.
12"X12" panel: $200
15"X15" panel or canvas: $315
24"X15" canvas: $500
Other sizes are possible, just ask. I welcome the opportunity to work larger if you wish.