Correction: 8 panel. Commonly referred to as a "Newsboy", or "Baker boy", or "Big Apple" cap. A lot of companies make them these days, so finding one similar to his shouldn't be too difficult. Most are "cheap", some are dirt cheap, a good one should run you in the $30-75 range. I'd recommend looking at Mucros Weavers' caps--they're well made, hold their shape (unless you abuse them), and comfortable as long as you get the right size for you.
Look at you with all that knowledge and stuff!