Cellebrite's entire business is building these kinds of exploits into its shrink-wrap software sold to thousands of law enforcement agencies, including po-dunk municipalities that presumably can't afford federal government contracting rates. I'd guess that if they're quoting $15k, they're going to run the software they already have.

They are not know to be effective against current iPhones, but they do advertise their ability to break all Androids and older iPhones via USB on their public website.

Well, from the FBI's perspective, they may already know the data on that work phone is worthless, but they just pretended it's not to get the precedent against Apple.

From Cellebrite's perspective, they should've probably asked more like $1.5 million to solve "such a valuable case", as the FBI has made it to be in public (and if this is indeed that contract, which it may not be). Apple also helped there by talking about how much of a burden it would be to unlock it.

Maybe this was the sum quoted by Cellebrite.