The very best figured walnut. Is 50-100+/bd ft ever reasonable?

[al ladd]

It seems to me like the price asked for the most beautiful rare woods has skyrocketed lately, at least for things I look at, which includes figured claro walnut, and koa. https://nwtimber.com/figured-lumber/claro-walnut/curly has always been my source when I need something special. I think both these items are affected by a dwindling supply and changes in land use/horticultural practices, in addition to the explosion in prestige-oriented amateurs buying supplies online. A few years ago I could buy grab-bag style "boxmaker" packs of claro for reasonable bf cost. Not anymore.

[Mike Cutler]

Yes, that is the going rate. Highly figured walnut, especially Claro and Bastogne,have always been very expensive.
Depending on what you intend do with it, will determine whether or not it is worth it.
BTW, shotgun stock blanks can run significantly more per bd/ft, than the piece you are looking for. It's not hard to move into the $1K per bd/ft range.
Everything is demand.
That is an exceptional piece of material you're looking at. I would buy it.