Of the many fine options available, I went with 21st Century, as everything else I've bought from them has been excellent, and the neck turning setup was no exception.
So far as your shopping list, you can just select one of their 'complete' packages, which will include everything you need in one shot, i.e., lathe, turning tool, cutter, case holder and driver, expander die body, and the turning and expander mandrels. That's the complete package; if you opted for the non-powered lathe then you'll also need a driver of some type. I went with the powered option and it's excellent. There are YouTube videos showing the non-powered version and that also seems to work well.
I'd add to that a quality tube micrometer; I like the Mitutoyo 115-313, but there are many options available. Additionally, a micrometer stand is a very handy thing to have if you didn't come equipped with more than 2 hands. I think the Moore and Wright MW279-01A is a nice one in terms of value. Finally, a lube of some type; I use Lee lubricant for sizing, so I also use it for turning. It's very easy to clean up, which is sort of the selling feature for me. Likely any decent lube would work fine.
Back to the turning setup, can't say enough good things about the 21st Century stuff. You hear a lot about how horrible neck turning is, etc., but honestly, it's incredibly fast and easy with their setup; takes very little time and produces excellent results.