So it’s not money laundering but there are things called Buyer’s Clubs which are used to artificially inflate the prices of collectibles. It has trickled into vinyl now. The basic idea is say you want to inflate the price of Stepping Into Tomorrow. And I want to inflate the price of Joey Dosik. You sell me your copy of Stepping Into Tomorrow for $300. I sell you my copy of Joey Dosik for $300. That raises the median value of both albums and buyers see the recent sales price and sellers all see the crazy price it sold for and raise the price of their copies.
The other option I’ve seen is that sometimes you’ll see a brand new buyer with no feedback bidding really high on stuff like eBay. It’s often a plant/someone in a buyer’s club. They bid the price up a lot. If they win the auction, popsike and eBay still register the sale. Person with the new account doesn’t pay, perceived value of the item has gone up and when that item goes up again, whoever else bid on that auction says “well that Joey Dosik sold for $300 last time...if I buy it for $200 it’s a steal!”
this has happened with the Music Matters BN and some people in the MM Facebook group got suckered into it. One guy paid $450 for Speak No Evil but was bidding against someone with zero feedback on a throwaway account. They thought they got a deal because another copy had just sold for $550 a week before.