Life is just too short to tolerate crappy optics.
Hear hear and Amen. But the hard part is drawing the line between crappy and non-crappy.
Are there exception-to-the-general-rule (that you get what you pay for) bargains to be found sub-$150 new / sub-$100 used? I think the answer is yes, but I'd always limit them to rimfires, and stay with low-powered configs. I've used Millets, Bushnell Banners, Bushnell Legend, Muellers, and some others, and in the end, they're just not worthy for any centerfire that might be relied upon for either self-defense or a trophy animal. Now don't get me wrong, this is due *primarily* due to low-light clarity/resolution, not fear of failure to hold zero, but still - resolution is very important for hunting, since game move most in low light.
In fact, I don't even go that low any more - divested of all those. Now the lowest I go - even on rimfires - is Nikon Omega (which is a very good scope), or Bushnell Elite 3200, or Burris Fullfield II, or Leupold Rifleman.
Obviously the number 1 priority (key feature) of a scope, by far, is holding zero (i.e. not breaking), which is worth noting that this has zero to do with glass & coatings quality. But glass quality and general quality & durability pretty much go hand in hand. And the other aspects are important too - turret features, glass quality & coatings quality, magnif. options, on and on. The problem with many cheap scopes is, they may break on the LAST shot at the range before you leave when sighting in, or the ONE/LAST shot you took last season - then you don't realize this until you miss the B&C buck the next season due to the scope, and it's too late.
And yeah though, due to glass quality, you've GOT to stick to no more magnif than 3-9s on real cheap scopes (sub-$100), and no more than 4-12 on sub-$200ers. Even though I eventually divested of them, I had good results with 1-4s and 1.5-4.5s and such from Bushnell Banner back when.