How much should a person spend to get a decent power conditioner?

Even if you have obvious noise problems, a power conditioner is likely going to be useless, especially for component-induced noise from amp transformers and the like. If you have audible buzzing, hiss or hum, try using a "cheater plug" for your amp and preamp cables. If the noise ceases, a power conditioner definitely won’t do anything for you. There’s a reason why so many supposedly great power conditioners end up on the used market. Most are complete snake oil.

If you want a lower noise floor, put your money where it counts: in a better amp and preamp, or integrated. No power conditioner can substitute well designed circuits with high quality parts.

Helo: you are fortunate then to have a reliable power company.  I just installed the Parasound Halo A21, and I have not experienced any buzzing or popping, I am wondering about the possibility of positively affecting the sound stage.  My power company is notorious for surges and outages so it's not just aurally motivated, but protective as well.  I am curious, if it's all snake oil, why would people invest thousands of dollars for conditioners and power cables?

It’s sounds like you are after both surge protection and trying to improve the sound? On surge I use a whole house, not expensive, but you need to replace when the pilot lites indicates the MOVs are no longer effective. Plus I use a very large commercial isolation transformer with its own surge protection panel feeding a dedicated subpanel to dedicated lines. The wiring isn’t costly, but the iso-transformer can be unless you are sourcing the naked transformer and have a way to install it to meet applicable code. (My unit is about the size of a large air conditioning box and sits outside- it is weatherproof and was built to spec as a finished product).
My concern about black boxes that actually do anything is that they affect the sound. I haven’t used any of the (end) point of use for a while for the main hifi for that reason, though virtually every other expensive appliance and my second hi-fi system do use point of use surge protection.
Dedicated lines are nice, no guarantee of noise free from common grounding with house and no surge protection. I would look at subpanel type protection for the dedicated lines if you can do that.

I’ve never messed with high powered regenerators which can get costly -- I was always concerned when they were (only available as) smaller units that they constricted current to the amps.

I am wondering about the possibility of positively affecting the sound stage. My power company is notorious for surges and outages so it’s not just aurally motivated, but protective as well. I am curious, if it’s all snake oil, why would people invest thousands of dollars for conditioners and power cables?

People invest thousands in conditioners and power cables because of their audiophile nervosa/insecurities and placebo effect. They also have more $$$$ than they know how to spend. First World problems. Manufacturers take advantage of this fact. If power conditioners really make such a big difference, why do companies like Parasound not produce any?

I’m not saying they can’t make a small improvement in a home with noisy AC, but most noise is component induced --from noisy transformers or less than ideal grounding schemes. Incoming AC is rarely the true culprit.

If you’re most concerned with surge protection, get a Brick Wall:

https://www.brickwall.com/pages/the-worlds-best-surge-protectors

These don’t rely on MOVs and will protect as well as any four figure "conditioner."