Depends on who has what posted; sometimes you need to jigger the terms a bit. "tsa knife" gets you 6 hits (mostly Classic SAKs and knockoffs). "multitool lot" gets a few hits for seized knives and used Micras. "leatherman squirt used" gets a lot of hits, including P4's for $11 shipped and a S4/P4 set for $30 shipped (Buy it Now price in both cases). Just poke around; if you're the in market then the 5 minutes you spend plugging in search terms might save you a couple bucks. The original 25-year warranty applies to the little guys too...

(Standard Disclaimer, no affiliation to Ebay or Leatherman, etc.)