You are correct.... the brass is the most expensive part of the cartridge.
Reloading is a good "hobby" to get into.... Many times, if you shop, you can find a good press for under $100.... then get a good beam balance scale for weighing powder. In reality, you could reload with just those two items.
For convenience, you might want a powder dispenser, to speed up the process a bit.
A priming tool of some sort is very nice to have.
When you reload a few boxes, then you start thinking of other tools to make it more efficient. Trays to hold your cases while loading, etc...
I've been loading for 53 or 54 years now.... I've used RCBS single stage, Lee single stage and progressive, but currently am using a Lee cast iron 4 station turret press..... mostly because I can set up each die, and not have to change them out every time I go to a different step in the process.
It's difficult to save a lot of money loading 9mm.... factory ammo is just too inexpensive. The best part of loading is that you can tailor a load to a specific firearm.... plus you have the added security of knowing you won't "run out" of ammo, if there's a shortage....
I agree, though..... I won't shoot someone else's reloads, unless I know them personally, and trust them completely.
Bad things can happen when you shoot a careless reloader's ammo....
Ask me how I know....