First off nice to see a survivor cj!
1st question: Body Lift, Shackle Lift, Suspension or SOA?
Well just like anything else you are going to hear alot of different things. I have a '76 CJ7 with a 304 and I have a 4" suspension lift. I believe it to be a Rough country. It has been on the jeep about 9 years. It is stiff and rides pretty rough. CJ's w/ spring lift ride rougher than stock if using CJ springs. A real common swap is to do a YJ spring conversion which are "softer". There are a handful of companies that makes lifts for cj's. Rough Country, Skyjacker, etc. Priced around $600.
1" - 3" common size, Cheap. <$200. Just allows for larger tires.
I'd say don't go more than a 1". Not a fan. I plan to put a 1" Daystar soon.
Small amounts ok but a lot and the springs will be walking around on ya. Shackles run <$200 normally.
Spring over axle. Gain several inches by just moving the springs to top of the axles instead of underneath. Never ran it but requires modifications to the axles. Not sure on cost.
I am in the middle of quoting a YJ conversion with Old Man Emu springs. It is only about a 2.5" lift but will increase flex and made it ride a ton better. However it is going to be over $1k; about 2x's the costs of most lifts.
If things go well I will have a 4" lift for sale.
Seriously though, let me know what kind of lift you are thinking and we can go from there.