I usually get like 20% or less... sometimes they're hard to even give away.
It's very hard to get anything like that much off a Mac, since Apple appears to have pretty tight control over prices, even as charged by third parties.
Before buying any Apple hardware, it's worth looking up a couple of sites that suggest when the next release cycle will be for a given item and what specs are expected in the next release. The one I use is https://buyersguide.macrumors.com/
After years of waiting for a non-butterfly keyboard, they released a working Intel based MBP, but almost immediately made it worthless by announcing the migration to Arm. They even "rented" prototypes using A12Z chips for developers to use to prepare their apps nearly a year in advance. Hardly a stealth endeavour.