Bart was a man who knew a bargain when he saw it. Sure, he could have gone for an everyday ten gallon hat, but for just two dollars more he could get the fifty gallon size.
By the way, a ten gallon hat can only hold about three quarts of water. So how did it get that name? One theory is that Mexican vaqueros (or cowboys) wore hats with braids around them that they called tan galon, which meant "fancy hat." American cowboys misheard this phrase as "ten gallon" and the name stuck.
This was a fairly quick little vector drawing. I had a tough time with that frakin' hat though. Specifically the curved brim. It took a lot of attempts and finessing to draw a brim that was both ridiculously widened but still recognizable as a cowboy hat. The wispy clouds echoing the shape of the brim was a happy accident.
Originally the hat was even larger than it is here, but I found that the bigger I made the hat, the smaller the character had to become. I had to reduce the size of the hat somewhat for the cowboy to even be visible. I thought that having the hat break the boundaries of the background would make it seem bigger.
Drawn all in InDesign. A lot of people are surprised when they find out I draw in InDesign rather than Illustrator. InDesign has most (not all) of the same drawing tools as Illustrator, and it's easier to use, IMO.