Let me try again. I misinterpreted "bills" as being $1K rather than the normal $100. I actually went to the linked page, and found the price of the pen to be $374.50, which is close to the 4 bills you mentioned. Yes, that's expensive for a pen, but not what I was mistakenly thinking.
I bet they are a hot seller these days.
$400 is a lot for a pen in these environs. I don’t begrudge him that nor am I a class warrior. Just $400.