It doesn't really start at $250k. It's just a dumb quirk of the AWS marketplace participation process.
As a vendor, if you want to participate, you have to have a public listing page with a price. But many vendors don't actually want you to initiate the buying process that way. They want you to talk to them first, negotiate a deal/contract, and only then handle the payment through AWS marketplace (presumably with pre-committed spend you already have on AWS) via something called "Private OFfers"
So lots of marketplace pages have an absurdly high public listing price to discourage people from using that route.
