I got that, it's a common explanation... A person has their expectations linked to their opinion of the value they relate to the money they have an spend.
But your expectation of what $900 should get you may not be the same as the expectation of someone else... That was my point.
I've met very wealthy people who were pretty much as to what elegance actually is. They thought elegance was a matter of how expensive something was... Therefore, their expectation wasn't based on elegance, but on cost.
Many years bought a turtle shell pendant (farmed turtle for this purpose, and for meat) from a rasta jeweler in Negril, Jamaica. It was quite unique/beautiful, almost like a sunrise. It was a little raw in finish but I was able to negotiate a really low price for it. I polished it, put a nice gold clasp on it, placed it in a classy-looking box, and gave it as a gift to someone. She thought it was a way more costly piece than it was. She didn't ask me how much I paid for it, she simply applied the value of her emotional response to it.
My point is... Expectations are usually linked to subjective feelings... And so the matter of value can be as well.