There's precedent that points in both directions. There was a fair amount of research when there was a push for transparency in hospital pricing for services in the US. One piece of research: https://portal.ct.gov/-/media/OHS/Healthcare-Cabinet/2021-Me...

You'll see there's some cited court cases that supported pricing as a trade secret, and some that held it was not.

It seems to be still pretty muddy legally.

Sure. Broadly, a trade secret under state and federal law is "information that derives independent economic value from not being generally known to the public or people who can obtain economic value from it and is the subject of efforts to maintain its secrecy that are reasonable under the circumstances." Price lists could clearly fall under this definition, and they do! Here's an 8th circuit case where the plaintiff "adequately allege[d] that the information that was purportedly misappropriated— ... pricing information ... qualifies as trade secret[]." Ahern Rentals, 59 F.4th 948 (2023).

I've signed and written quotes that have those provisions. What the legal standing is, I can't comment on because it never came to that.

This is with the obvious caveat that public tenders are the exception, but only after it's awarded