Lots of good advice, and many different directions.
I'm a fan of rebuilding the old production rods for use although I haven't done much in the last 8 or 9 years. If you chose to go that route, pick up something cheap for the first one and don't worry about collectability. If you do a nice job but don't like the action, they still make nice wall hangers (decorations).
And I did say rebuild, not restore. Jack had some good advice on that. but don't do a rebuild on anything that has reasonable collector value because if you rebuild rather than restore, you destroy much of not all the collectability.
However, if you do chose to restore, rather than rebuild for modern lines, old silk lines can also be restored. I have a few lying around. I've also heard that you can get new silk lines for "fairly" cheap now, but I only heard that. I have not observed that. They might even make non-silk lines suitable for the old cane rods.
JeffK dissed the post war Japanese rods. I don't necessarily agree or disagree with that. It depends on what you are looking for. If you are looking for a pretty rod or one that is somewhat collectible, than I agree that those definitely are not a good choice and should be avoided. Many (of not all) of those were just milled and slapped together and have gaps and in general don't look good if you look closely. But many actually have decent action if you are just looking for something to fish with. So, if you are looking for a rod to practice on and don't care about destroying toe collector value and just want it for fishing, ... it might not be a bad choice. They are fairly easy to identify once you have seen a few. The milling quality definitely sucked.
I'm pretty sure my steelhead rod is post war Japanese, but there were no markings when i got it. It had gaps that sucked up the varnish when refinishing. I think I ended up using tongue oil until it was done "sucking" and then several coats of spar over that. Hell, I even used some wood filler. It was awhile ago. It looks alright, but frankly I don't care that it isn't the prettiest rod. I like the action for steelhead. It's a relatively slow action 9 foot and tosses a 6 or 7 weight line well. I use a 7.
I'm guessing those boxed sets (with the box) can be had for between $100 and $200 with that unused condition being the higher end. I wouldn't touch any of those. but I might buy a used one without the box if I could get it for no more than $25. My steelhead rod was actually a freebee. It was part of a bundle of rods that I bought. I probably have less than $70 bucks in to components in it and all that is original is the cane itself.
I'd say the three biggest big mass producers are/were
Horrocks-Ibbotson
Montague
South Bend
There were several smaller produces, and a ton of brand labeled rods.
for example, I have had a couple Shakespeare that were made by South Bend.
Montague made a ton of rods for other people. King Fishers are quite common, and I think they were sold by Montgomery Wards or Sears.
H-I at one time was the largest tackle manufacturer in the world.
All three of those rod manufacturers made some good rods that are somewhat collectable now, but they also made some very inexpensive rods that have very little collector value. for example, if you pick up a Montague flash, that is a good one pt practice on. I think I have 3.
Then you jump up a little bit in quality. Grangers are collectible. Some more than others. I once sold a Divine for a friend and I think I got about $250 for it. He garbage picked it. He also garbage picked an old H-I. It's a very nice rod, probably early to mid 1930s in very nice shape, but I set a $100 reserve on it. When it didn't sell, he gave it to me for selling the Divine. At the time I figured it was worth about $75 and that ended up being the high bid. It would probably sell for over $100 today. For it's age, it is in really nice shape and definitely restorable.
I only talked about rods that I have or have had, and I only scratched the surface.
I never got into the more expensive stuff because I'd be half afraid to use them.
There is a lot of labor in stripping an old rod down to the blank and rebuilding. You have to love doing it. Otherwise you would be further ahead to buy a blank.
No matter which route you take, keep checking back here. Advise is free, and many of us like giving it.
Disclaimer: I am not trying to sell any rods. I just like the old stuff.