I wouldn't worry about it. I think my little lead-filled copper cylinders work great (I have virtually zero caking when I empty my tumbler canister), I think you can probably do well with other kinds of media. Just make sure it's non-sparking. .75 or .69 caliber lead round balls will probably be fine.
The equipment you need is pretty light to get started.
Harbor Freight Rock Tumbler double-drum $65:
https://www.harborfreight.com/dual-d...ler-67632.html
Assuming it has the same power, you might do better with the single-drum version because the double-drum version is not strong enough to spin two full canisters at the same time anyway:'
Harbor Freight Rock Tumbler, single-drum $53:
https://www.harborfreight.com/3-lb-r...ler-67631.html
12-ton Hydraulic Press $140:
https://www.harborfreight.com/12-ton...ess-33497.html
Digital Scale $12:
https://smile.amazon.com/dp/B01E6RE3A0
40 screen $10:
https://smile.amazon.com/gp/product/B00KFS99C2
30 screen $10:
https://smile.amazon.com/gp/product/B00KFS0QBU
20 screen $10:
https://smile.amazon.com/gp/product/B00K3725WQ
Puck Die $50:
https://www.woodysrocks.com/store/p2...uck_Press.html
Propane Burner $40:
https://smile.amazon.com/GasOne-B-51.../dp/B07W733BFQ
There may be cheaper options for some of these things elsewhere. Fly's puck was cheaper (and all aluminum, which I like).
You'll need a few other odds and ends, like Tupperware containers, plastic spoons, plastic spatulas, and ball mill media. You'll also need at least a gallon paint can to make charcoal (or just buy charcoal). If you don't have something to cook the charcoal on, you'll need that, too.