My personal answer, by the way:

If I want a taste of something, no way am I spending more than $50. So that actually keeps me out of D&D 5th, which, you know, whatever. Maybe I’ll find used copies at a later date.

But once I’ve had a taste and I like it? I don’t know that I actually have an upper limit to what I’ll end up spending. Opportunity costs keep my ongoing burn low, like in the $50/quarter range, hence my curiosity about starting a Patreon if folks like reading my takes on games and they’d find my reviews, analysis and AP useful.