If you mail Don Knuth about the error you found in TAOCP, he'll send you a check for $1 -- he used to do that, anyway. People tend not to cash the cheque, but keep it.
This line is classic Knuth:
only 9 of the first 275 checks that I've sent out since the beginning of 2006 have actually been cashed. The others have apparently been cached.
> Knuth offers monetary awards to people who find and report a bug in TeX. The award per bug started at US$2.56 (one "hexadecimal dollar"[41]) and doubled every year until it was frozen at its current value of $327.68. ... Due to scammers finding scanned copies of his checks on the internet and using them to try to drain his bank account, Knuth no longer sends out real checks, but those who submit bug reports can get credit at The Bank of San Serriffe instead.
(https://en.wikipedia.org/wiki/TeX - this is about TeX, though most of it is generic over all his various cheque schemes: https://en.wikipedia.org/wiki/Knuth_reward_check)