I think you are selling yourself short on your commissions. I was at a GP one time and asked an artist there (i am keeping his name removed because he is on DA and don't want him to think bad) how much he charged for a full color playmat. It was something like $600. I think $150 for that wound reflection one is actually VERY reasonable. I do graphic art for a living, so one thing I think about when people ask me how much for something is, "How much is my time worth to me?" How long did those playmats take you to do? I think when I start to do commissions I will start around 250-300 for a full art playmat. less for single characters, etc. More if it is original art. I am going to pick up some watercolors for my next one. did you use the watercolors that are in a tube? or the hockey puck kind?