Determining street art value is difficult then again, this can be said about all works of art no matter who created it or in what form it was created, with what, and which materials used.
My picture depicts a street artist who uses spray paint and brush for his art that he does protecting his lungs by wearing a respirator and his eyes with goggles meanwhile, lighting is provided by a battery-powered portable torch or perhaps, by extension wire connection to some nearby store.
Work is done at night on a designated street corner or niche unofficially mutually agreed upon by the Saint Catherine street buskers association this allows fellow buskers, street artists, musicians et al space to operate without getting hassled by others.
As the image shows a considerable amount of passersby find this operation interesting enough to check out and a live demonstration retains their attention.
After witnessing the artist in action some check out some of his finished works shown in my second picture.
This my contribution for WP single word prompt:”VALUE”.