Before there was Linkin Park, there was Xero. Xero was formed in 1996 by current Linkin Park members Mike Shinoda, Rob Bourdon, Brad Delson, Joe Hahn, and Dave "Phoenix" Farrell alongside then-vocalist Mark Wakefield. Xero would go on to put out a self-released demo in 1996 with a second version out in 1997, and then ended before eventually recruiting vocalist Chester Bennington and changing their name to Hybrid Theory in 1999 (and then Linkin Park later on).
Then in 2020, someone bought the 1997 cassette demo for $4,500 on Discogs. The sale placed twenty-second on Discogs' 50 Most Expensive Items Sold in 2020 list, which included a lot of Nirvana and Negative Approach. You can check out the full list here, which was topped by a 12" copy of Scaramanga Silk's 2008 single Choose Your Weapon that sold for a whopping $41,095.89.