A spool of filament is worth just as much as you purchase it, as it lays in its box, but nothing more, $14… A mere foot of PLA filament means absolutely nothing laying on the spool.
But what about potential value, like potential energy? Can you even quantify it? I had this thought cleaning off my “creativity desk” at home. I had a few washers from a project and a random foot of filament on my desk.

A few months ago, I created a set of plastic washers with that foot of PLA. These washers are now valued at $1. If I were to make washers out of the 1 kg spool, then the spool would be valued at $1000!
But what did I do with those washers? They weren’t just washers; they were spacers for a Wayfare dresser which was sagging and making the drawers drop out of their rails. These spacers are the solution which saved me from buying a new dresser. That foot of filament is now valued at $500+. The entire spool is now $550,000!

These values make a lot of assumptions about demand and absolute value; however, the point is the same. How we frame what we do and what we make dictates the value. I see these spacers as $500 (and so much more because my wife is now happy to have functional furniture) because they solve a $500 problem.
Mindset is everything.