The ‘co-’ in ‘commissioning’ is important: if you commission an icon, you will be initially engaged in negotiating the icon design. This is a creative process in which the iconographer learns how best to serve you towards producing the final image.
The painting of an icon is labour intensive and this accounts for much of its cost. You can get a sense of the working process here.
Among other things, he can send you structured costings to cover a range of options. Please don’t hesitate to make contact, whatever your interest or circumstances.