[tkhattra]

I have one for $7.68 ($2.56*3). Alas, it was for some minor typos and grammatical errors in SPOCS [1], not "real" math errors in TAOCP. Never plan on cashing it in though. And I can't remember where I stashed it, so there's that too... :)

[1] https://www-cs-faculty.stanford.edu/~knuth/cs.html