Whats a good economical way to test the electricity on a circuit?

Relax. The one thing we know for sure is its noisy, dirty, whatever you want to call it. The other thing we know for sure is if you do find something to measure and quantify this it will do absolutely nothing for you. Because we already know its noisy, and we already know what to do about it. Actually its even worse than that. Because if you measure something then that's what you think needs to be fixed, and all it does is set you up for someone's marketing story they want to use to get your money. 

So what you do instead is talk to people, read reviews, listen to different things, and buy whatever improves the sound. Power cord, fuse, conditioner, TA-102 tape, TC, outlet covers, whatever. All these things actually work and can hugely improve performance. I have no idea whatsoever how they made the AC sine wave look different on a scope. Nor do I care. Nor should you.

Almost forgot! There is one free and very simple test you can perform to hear for yourself just how much noise there is in your AC. Get your system nicely warmed up. Listen to your favorite music. Go to your panel, flip off as many circuit breakers as you can. Ideally everything but what's needed for the system, but for sure do water heater, stove, refrigerator, spare rooms, stuff like that. Go back and play that same music again. The huge improvement you just heard- blacker background, clearer details, improved dynamics, with less grain and glare - is all due to the reduction in noise from separating the system from all those other circuits. You will hear it. And once you do, you will understand why you do not need no meter. Because you have something better: ears. 

Go and listen. You will see.

I get what your all saying.. makes sense.. and not sure if im coming off nutty but i am pretty relaxed.. just wanted to play around with some measurements.. especially to see how well these PC, conditioners, etc are working.. Thinking of putting a dedicated line in.. aside from ears.. but just wanted to play around with the idea.. so if i shut off everything.. except breaker line to audio system.. that would get the same results as a dedicated line?