So first, I agree the most important question is whether you and your family can comfortably afford both.
Assuming yes, then we can’t make this decision for you, but I would suggest a framing that might at least clarify the nature of the decision.
I would personally start by banishing the word “prestige” from my thinking. The name on your sweatshirt doesn’t have the impact some people seem to think. What is true is sometimes some colleges are better networked in some particular job market or industry/field, but that’s not the same thing as generic “prestige”. And the same institution can have stronger and weaker networks in different places and/or fields. So if it helps, you can think about actual, real world networks you might be interested in. But I would not think about generic “prestige”.
I then also suggest you think about resources, including access to resources. This is a legitimate plus to WashU–it is a highly resourced institution, particularly on a per student basis. It has a large endowment, gets a lot of research funding particularly given its size, gets operating revenues from the medical system, and so on. Among other things, it uses those resources to offer a robust variety of academic programs (including a lot of cool interdisciplinary options) with relatively modest classes sizes, lots of support for student activities, and a very swank campus in an excellent location (I note it is right across the street from a truly world-class park, Forest Park, and there are also Metro stations on either end of campus that can take you quickly downtown).
So that’s attractive.
That said, Honors programs are basically about trying to close that sort of per capita resources gap by devoting disproportionate resources/access to certain favored students. The degree to which that works for you can depend on the exact nature of the program and what it offers, and what you are looking for both academically and non-academically.
OK, so along with however you value the locations and networks, you ultimately have to decide if your practical use of resources at WashU would be worth the additional cost to you, in light of how you would plausibly use the resources at Barrett/ASU. That’s not an easy question to answer, and ultimately you are sort of guessing. But at least that is a sensible question to be asking, and you can investigate various academic and non-academic factors of interest through this lens to at least help your guess be as well-informed as possible.