heya; you can try www.gag.org, the graphics artists guild. they publish yearly standard fees for various graphics projects. be sure you know what rights you are selling. if you give them permission to use the artwork once, but you still OWN the rights, that should be one price, but if they want to buy the rights, then it should be much higher. as an example, let's say you charge 200$ for one use of the picture. now, the next time they want to print your picture, they owe you another $200. if you sell them all the rights to the picture for $200, they can print that as many times as they want, and you don't get any more compensation. logos, on their letter head, on their business cards, on their trucks, t shirts, mouse pads, coffee mugs, hats, pennants, billboards.... they get all that for one price. generally, it is best not to sell the copyrights to your art, but to sell permission for limited use of the art. so just keep in mind not only what the picture is worth, but what use they will get out of it. (as well as how much you need to make, what is reasonable for their size of business, etc.)