First, I'd look at what is really causing your failure. If it's a problem related you your Z-Wave network in general (e.g., lots of traffic from S0 or power reporting devices, or some device with misbehaving firmware), it may not be these devices and could persist even if you replace them or move to an existing hub. I'd look into that first. If you aren't sure how, I'd start by sharing more information about what you mean when automation "fails," and someone can probably help you out. It's important to note the difference between an app not sending a command and a driver sending a command but the device not responding, among other places a breakdown could happen.
That being said, going back to the original question: if you want under $35 these days, you'll probably have to look at Zooz, at least among major brand names. You might be able to find GE/Jasco for under that price point, but there are multiple generations of these, and I'd be sure that whatever you're getting is not so old as to be 300-series (at least). I can also find a few less-common brands with a probably basic feature set (Ultra Pro?) in this range as well, but some people prefer support, firmware updates, etc., that normally come with a major brand name.
If you don't mind paying a bit more, Inovelli is one contender, as you note. They are what I'd use because I've gotten used to using the LED bar for "status" (e.g., hub mode--it changes color) and "notifications" (e.g., blinking when a door is left open). And because they come in both Zigbee and Z-Wave flavors, I can put a few of each around my house and get a solid backbone for both mesh networks. So, that's what I'd do--or have done, really. (You might be able to find used "gen 2"/500-series Red devices on the secondary market if you don't mind that, as there are people like me who ripped out most of theirs to replace them with the new 800-series models.) If you're getting a lot, keep in mind they have 5- and 10-packs for a (slight) discount compared to single devices, though as you've noted, they no longer offer the cheaper, less-featured "Black Series" devices.
Or there's the original multi-tapper, HomeSeer. However, until recently, I've found their products overpriced for what they do. They do occasionally go on sale (their HS-WX300+ is now $49 instead of $59 USD, somewhat surprising given that a HomeSeer "sale" normally means $58), and they've added some features (finally, disabling local control if you use smart bulbs!), so it's not as true as it was. But I still prefer the Inovelli-style LED bar, and if you want Zigbee too (or to match other devices), they are all Z-Wave.
I'll ignore Lutron since they aren't cheap (except Picos) and require an initial bridge or main repeater investment, but they have a rock-solid reputation if you're open to other options, too.