Here’s an amusing part of my collection, the highest denomination banknote ever issued: a $100 trillion “dollar” (10^14th) Zimbabwean note issued in 2008. The actual monetary value of the note when issued was somewhat less that the worth of 8 ounces of used cat litter. Shortly thereafter the Zimbabwean currency system totally collapsed with the locals instead temporarily adopting 6 packs or Heineken beer (really!) as a basis for economic exchange until the US dollar became the de facto currency.
In the meantime, Zimbabwean currency in various denominations from a few hundred millions up to the pictured 10^14th became available for amusement purposes for a (US) dollar or two on ebay. I bought twenty or thirty of the pictured notes and gave all but two away as joke gifts. But, as it turn out, the joke ended up being on me. Fourteen years later, the highest denomination bill ever issued has become scarce and is now selling for $100 to $300 US dollars.
One wonders whether some enterprising Chinese group has started counterfeiting the notes yet? (Another story but the Chinese counterfeiters are the bane of the existence of collectors of pretty much anything valuable.)
Well, Dementia Joe may try to give Zimbabwe a run for their money. But a hundred trillion is a big number.