OK, I think I can help, but mind you, I'm a guy who has been reloading for years without a progressive press. I've seen them, I've used them, they often work quite well for shooters, but as you are saying, there is an amount of ammo you need to reload in order to make them pay for themselves. You are also correct that you need a bunch of additional equipment other than just a press and dies.

So let's get started for the minimum amount of money possible, and then you can work your way up to progressive presses (like the Dillon) when you see a need for it.

First, you don't even need a bench-mounted press to reload, especially on handgun cases, which are typically straight-wall cases. You can get by with a Lee Hand Loader or Lyman 310 tool:

Lee Hand Loader:

https://leeprecision.com/breech-lock-hand-press.html

This press takes standard reloading dies, so any investment in dies you make can be used in a single or multi-stage reloading press.

The Lyman 310 tool has been around since the late 1800's. It works very well for straight-walled cases, but it doesn't take "standard" (7/8-14 TPI) dies. 

https://www.lymanproducts.com/lyman-310-tool

If you want to buy a 310 tool, I would look in garage/estate sales, FleaBay, etc. Don't buy one new - there are zilllions of them out there in the used market, and they last forever.

OK, you'll need a way to measure powder. There are two ways you can go with this: You can measure by volume, or by weight. Most all modern reloading manuals go by weight, so I'd advise you to obtain a good, but basic, scale. Lyman, Lee and RCBS all make a good, basic mechanical scale as well as some inexpensive digital scales:

https://www.lymanproducts.com/brands/lyman/scales-measures

https://leeprecision.com/powder-handling/lee-safety-powder-scale/

Heck, why not just show all of them:

https://www.midwayusa.com/powder-scales/br?cid=9211&customerSelectedSort=False

If you have money to spend, you could then get a "powder throw" - a powder measure that allows you to just pull a handle and throw a pre-measured charge. Powder throws/measures can either be mounted on a press (which you can use even with a single-stage press) or on the bench, and then you move your case under the press. I use a throw that mounts on my single-stage press(es).

Then you'll need a vibratory case cleaner. There are several ideas on this out there - I still use a big vibrating tub filled with walnut shell media. It works. There are wet case cleaners, vibratory cleaners, tumbling stainless steel pin setups, you name it. 

Then you'll need some dies. In dies, you need either straight-crimp (for straight-walled pistol cases used in semi-autos) or roll crimp dies (for ammo used in revolvers). For pistols, you then have two more choices: steel or carbide dies. Carbide dies need less lubrication (and sometimes, no lube with clean cases). For steel cases, you'd better have a lube pad and some lube. Case lube is a little like the alcohol lubes used for medical procedures and "personal" lubricants used in the bedroom. You could use an oil-based lube, but oil can deactivate primers, and I don't recommend having it on the loading bench.

Then I would recommend having some "reloading blocks" to hold cases as they move through various stages of reloading. I have five or six of them, to hold 100 cases at a clip as the cases move through the process.

OK, if you've read this far, here's my philosophy on reloading and presses: I reload a bunch, but I no longer shoot IPSC or other pistol games that burn a lot of ammo. I go through maybe 1500 rounds of pistol ammo a year in at least three different calibers. I load the ammo where it gives me the highest return on my time to do so.

Cost/savings: I reload hundreds of rounds annually in various rifle calibers (each) - .30-06 and .338 especially. I can buy 7.62/5.56 inexpensively, but '06 and .338 add up very quickly to buy them pre-loaded. For someone of my age, I can remember when it seemed we would never run out of .30-06 ammo surplused from the huge stores of ammo from WWII/Korea. Well, it's all gone, and commercial .30-06 ammo costs at least $0.75/round now.

To your question of pistol calibers: 9mm Luger is a round where I'll buy more often than I reload. I keep all my brass, always. .45 ACP is a "wobbler" - sometimes you can find sales which make it a no-win to reload. .45 Colt? I reload. 9x21? I have to reload. 10mm, I reload. .38 Super? Reload most of the time. I don't have a .40 S&W, but the price of .40 S&W ammo isn't that high relative to others. .38 Special in target loads is a reloaded round for me. If I owed a .357 or .44 Mag, I'd reload those in a heartbeat.

I don't have a progressive press. I have three single-stage presses (RCBS Partner and a couple of Rock Chuckers), and when I reload, they get set up to do individual stages. I'll set up one press to de-prime (the Partner), then another to re-size (Rock Chucker) and another to prime (another Rock Chucker). OK, so now I have primed cases, which go into a tray.

Then I pull off the decapping die on the Partner, I put on the powder throw, and I run the cases through to charge with powder. A seating die gets mounted into one of the Rock Chuckers and then the rounds get a bullet added/seated/crimped.

At this point, a batch (100 rounds at a time) is done.

I run 100 rounds through in a batch. I deprime 100 rounds, then resize the same 100 rounds... on down the line until it is done. They get boxed and I re-charge the ammo tray with 100 more cases. I can get through 400+ rounds in an hour easily - with single-stage presses. I got the Partner as a prize at some game banquet, then I picked up the Rock Chuckers for $40 and $60 from garage sales.  

And for a beginning reloader, a warning, and I really mean what I'm about to say here for everyone who reloads:

Many of the older cases from a century+ ago make it possible with modern powders to at least double-charge a case, and nearly triple-charge a case. You MUST check every round visually to make sure that there is only a single charge in the case. Never have more than one powder open on the banch at a time. NEVER. This is especially important when you have both rifle and pistol powders. Pistol powders are deadly when loaded into rifle cases.  Never get distracted by someone talking to you while you're charging these older cases. There will be no over-flow, no powder dribbling out of the press, etc if you double-charge these cases. A second charge will go into the case cleanly, with room to spare with some modern powders.

Examples of the rounds I'm talking about: .45 ACP. .45 Colt. .38 Special. .44 Special. .44-40. A great example: With modern powders, you can fit a HUGE amount of powder into a case like the .45 Colt. You can load a .45 Colt to be every bit the equal of a .44 Magnum and then some. If you put that over-charged .45 Colt into an older Colt Peacemaker, it will come apart on the first round like a hand grenade.  To address this, some powder companies make a "fluffy" powder to take up all the room with a modest load:

https://www.hodgdon.com/trail-boss/

This powder will give a very modest pressure in a full case in old cartridges like the .45 Colt.  For safety, I recommend trying to find a powder/load when you're starting out that gives you 90% load density, ie, the powder will take up 90%+ of the room in the case.