The CH Swag-O-Matic is limited to dies made for .30, .357/.38, .44, and both .45Colt and ACP. I have seen both the single dies, and press itself come up on variuous auction sites from time to time. I do not have one, nor have ever used one so can not comment in that regard. The advertisements for this quite obsolete system do not mention having a capability for jackets of any sort, but do mention zinc washer capability. CH stopped making or selling this system prior to 1970. I would be very hesitant to buy any tooling that isn't supported by the maker: not unless you can afford to pay a machinist $80/hr to make replacement parts for you.
Besides the press and dies, you will need to purchace or make your cores. With mail rates so high these days, buying cores, or lead wire, cost about as much as buying finished lead bullets. If you made them yourself you would need a core mold and lead pot, or a wire cutter. And if you wanted to make jacketed bullets, you would need jackets (and I'm not sure if you can use them in the Swag-O-matic). Pistol jackets cost about 3 to 4 dollars per hundred + tax/postage.
So, $15 is just the start of your costs... But, if the system you have an opertunity to get is COMPLETE, part wise, and WORKS, using it will be a good learning experience. If you find you like swaging, you can always sell it and upgrade. If you find swaging isn't for you, well, you can sell it anyway. This strategy also somewhat smarter than getting a current $200 swaging system (CH has those today) and then finding you made a mistake.