There is no need for growth. Sustainability used to be a thing. But the wealthy do what the wealthy do with all their leasure. Turning systems inside out and on their head. Gaming it till the growth pushes everyone else out. And it's not likely to change till capitalists are regulated from existence.

Currency and markets can exist without capitalism. Sustainably can't exist with capitalism.

If we fixed prices for one thing, we'd have to do it for everything. In a world where resources aren't exactly infinite, that creates a huge problem; especially when you have to pay people who're producing this fixed-value commodity (because you need people for that) and you have to increase their wages to buy stuff that isn't fixed-value, like housing (since land is a limited, though abundant, resource).