I bought me a cobalt one about two years ago that I found deep in a corner of a dusty antique store. $13 bucks. Have seen two just like this go for over $50 on ebay in the past month.
I've dug a few different square and kinda barrel shaped cobalt inks. The only coner I've ever dug was a slightly melted amber. Same exact style as yours Badger. Swiz []