Lathe and especially mill tooling can be expensive if you have to buy the pieces individually, and new. If you can pick up a good package of a machine and tooling it can be affordable and even inexpensive, but that depends on opportunity and location.
People who sell (and resell) used machine tools, both businesses and individuals, often strip off tooling from package deals they purchase and sell the items piecemeal to bring in more return on their investment. If you can buy a lathe with all the tooling, it can be a bargain, but be aware that missing items can be expensive to replace, depending on how common they are and their desirability in the used market. Case in point, an older Atlas 10" lathe without a quick change gearbox can be bought for $300, but a steady rest for the same machine may sell for $100 on the Bay. A steady rest for an uncommon lathe may not ever be found.
If you are missing a piece of tooling and have a job that needs it you have three options: first, wait for the tooling to become available used at an affordable price, second, buy the tooling at whatever the current market price is, or third, have the piece made by someone with the proper equipment/tooling. For those networked in the metalworking trades, a fourth option is to borrow the tooling, but that depends on personal connections not available to people like the OP. The average Joe has to buy it new.
Kevin, you have worked in the trade long enough that you see bargains that most won't. Even Craigslist is less of a bargain for most listings, and you need knowledge to pick through what is there. Benchtop machines can be bought for modest prices, but have modest capabilities. They work OK within their limitations. They make good beginner machines, especially working with plastic, brass and aluminum. Would you be satisfied with a benchtop machine for your needs? I doubt it.
Any time you have a thousand dollars or more invested in a hobby that isn't your main interest, it can be described as "expensive." I have two lathes, a Bridgeport clone, and a Mill Drill, not counting bench grinders, drill presses, etc. I have a modest amount in purchasing all this equipment, bought most of the tooling used at good prices, and have the experience to use it. I got good deals on the tooling because of networking friends in the trade. I am taking up shop space that cost full price to build. I had to supply enough electrical power to run the stuff, which cost a fair amount, including three phase power to some of the machines. It all adds up. I use them for projects and enjoy them. I could have farmed out everything I have made on them to the local machine shop for not that much more than I have invested, and with fast turnaround. I would rather make the stuff myself as I like to run the machines and enjoy the satisfaction of a job well done. I don't expect to save any money by doing it myself.
By the way, I have the chance to buy a Hardinge LP3 turret lathe that holds tight tolerances for well less than $1,000. It has very little tooling with it. I'm not interested for two reasons. I would have to find and buy the tooling, and I have no real need (or desire) for a production machine.
Do you care to explain the above as to how it is an expensive hobby and how it is a significant investment 