You have several options, and which one you get is really dependent upon what you want to do. Here's the categories of lathe:
9" or 10" metal lathe:
These lathes are good general purpose workhorses for both stummel and stem turning. You can use wood turning chisels by using the cutter bit as your tool rest, and you can even cut threads with most examples. Entry price is high though, about $1000 new.
There are lots of brands in this category, but the Jet BD-920 is the favored choice. Anything new is going to be a Chinese import, and quality varies vastly from one brand to another. Jet seems to be one company that insists in better quality for their nameplate.
For used, you can step back 50+ years and find a good, solid working example of early and mid 20th century machinery. Atlas, South Bend, Rockwell, Sheldon, Hardinge, etc, etc. These machines vary in price from "affordable" to "what is he smoking". The relative condition is also vastly different depending on where it's been sitting (or being used) for the last 50 years. You *can* find good old lathes, but the prices can approach the cost of a new one.
The mini metal lathe:
With the exception of Taig and Sherline, these are mostly 7x12 or 7x10 Chinese imports. Quality, as above, varies vastly from one nameplate to another. Entry price is about $400 before any additional tooling.
These are really too small to be of use for turning bowls. They lack the mass that you need for stability when turning off-center blocks of wood, and also don't have the amount of swing you need in order to turn any but the very smallest of pipes. Folks that have these largely end up using them pretty much just for stems.
10" wood lathe:
The kings of this category are the Delta Midi and Jet Mini. I have heard mixed reviews of the Delta though - from tailstocks not lining up to the headstock being off axis. I have not heard the same complaints about the Jet lathes, however. Entry price, before chuck and chisels, is about $300.
full disclosure: I have a Jet Midi (JML-1014) and I love it. It has seen rather hard work over the last 5 years, and hasn't given me a lick of trouble.
These lathes have sufficient mass to be relatively stable while turning a stummel, but bolting it down to your workbench is still suggested. You can also use these to turn pens, bowls, cups, vases, and other objet d'art.
The biggest expense with this category is not the lathe itself, but the tooling that you need in order to use these to turn pipe bowls. You will need, at a minimum: spindle gouge, detail gouge, skew, roughing gouge, 2 jaw chuck (or 4-jaw with two jaws removed), and jacobs chuck. Your chisels are going to run you at least $40 each for good quality, and can approach $100 for top of the line. Don't. Cheap. Out. If you get the $20 set of chisels from Gizzly or Harbor Freight, you will be disappointed. You have been warned.
Contrary to popular belief, you can turn tenons on a wood lathe. You need to be careful and precise, and you have to practice at it. It takes time to be able to do it, but it is possible. I did it just yesterday. It takes slightly longer than doing it on a metal lathe, but the process is the same.
Rather than turn tenons using a wood lathe, you can opt to use delrin for your tenons. I've got a writeup in the stem section on how to go about using delrin.
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But, all this talk of lathes.... Strictly speaking, you don't even really need one to make pipes. If you've never made a pipe before, start with the other tool room essential - a drill press. You can drill stems for delrin tenons using one with minimal effort. In fact, Woodcraft and others sell self-centering penmakers vises that are perfectly suited to drilling rod stock or pre-fab stems for delrin tenons.
And obviously, you don't need a metal lathe to make pipes either. Anything you can do to wood and plastic on a metal lathe can be done on a wood lathe with practice. No, it's not easy, and it will take time to develop the skill, but if you ask me, it's worth it to have those skills in your arsenal. I have claimed this in the past, and I stick to my claims - but in a few short weeks I'll be returning home from the NASPC show with a mid 20th century metal lathe in the back of my Jeep. Certain things are simply made easier by having a metal lathe - such as cutting tenons or metal accent rings. And, frankly, they're useful for loads of other non-pipe-related projects as well. Personally, I think a well-rounded pipe making shop would have a wood and metal lathe available - because you just never know what you might want to do.
