In parts of the US (well, eBay.com) you can by bills of 50 trillion from Europe for very little.

In other words, Africa is a big place. Just say "Zimbabwe".

German 50 Trillion (Marks) _stamps_ from 1923 are (literally) a-dime-a-dozen because postal services had a giant amount of them printed for issue in fall-1923 - just to have the whole lot rendered obsolete by the November currency reform. Unstamped/new they're not worth the paper they're printed on. Verifiably used / franked actually on a postal package they are much rarer. Fortune reversal - the worthless item becoming the collectible...

I'd like to think that they would switch to scientific notation past a million…