So Nick Walker is sort of a poor-man's Banksy (in that he's a rip-off and you don't need to understand commercial appropriation in order to "get" his art), but his works are enjoyable nonetheless. His website has a few pieces in his gallery, although, frankly, I don't think he should be selling them. I think art should be free, for the public. That's why stylized graffiti appeals to me. (Side note: It's not really fair to say he's a rip-off of Banksy because how do you determine the "original"? Can there be an "original" since graffiti has been around since forever, and if so, how to you determine the original -- by chronology of the works or chronology of the popularity/recognizability?)
The images below are from his Black Rat gallery proper show.