Is a high priced Line Conditioner needed

You may need a power conditioner if the power in your lines is noisy or suffers major lag periodically. I am sure the power conditioner manufactures or their devoted fans will tell you it is essential, after all -all of what we do is manipulate power.
My personal experience was one that found no benefit from power conditioning no low power drags and most importantly my dedicated lines were noise free. I think you have to ask yourself those questions. There is no mandatory audiophile rule stating that you must have power conditioners.

The Cable Company will send you some line conditioners to try first, before you buy them. I would go that route. You never know what's going to happen when you put power products in your system.

I'm not sure what you mean by high priced, but:

I currently use a PS Power Plant Premier which can be had for about $800. I have been in this townhome 3+ years and have dedicated lines. Until I installed the PPP, there were easily heard changes in the sound of the system at various times. Most notably, there was a hardness in the upper mids that would come and go along with quick listening fatigue. The hardness was there more often than not. The PPP has removed the hardness and solved the listening fatigue issue for me.

In my previous two houses, I had dedicated lines fed from a Topaz isolation transformer (fed from the electrical panel) and that was all I needed for stable consistent good sound.

You won't know if your system will be improved or by how much it will be improved unless and until you experiment.

I have an audio store in my house, literally, and I went through the same thing.

I ran dedicated lines not because I wanted to I had to old house. I then tried different brands of power conditioners till I found one that I really liked, long story short I won't listen to a system plugged into a wall the sound just sucks.

A good power conditioner is mandatory for good sound.

A Monster is crap and will muck up the sound.

Stay away from power regenerators. It wll defiinitely be a waste of funds.