A press. I use a single stage for match ammo, and a dillon 550B progressive for bulk ammo.
Brass cleaner. Most use a vibratory cleaner I have switched over to steel media and water in a tumbler. The only thing I have to use is dish soap.
A trimmer. This can be anywhere from $20 to $300 depending on how fast you want to go.
Case lube and a lube pad.
Dies. For 223 dont bother with carbide you have to lube rifles rounds anyway.
If you dont get a progressive press you will need a powder thrower.
A good scale. I recommend digital but many do fine with beam scales.
Powder, primers, bullets, and brass.
I buy once fired brass for $5 per hundred at a local range this is very cheap.
For plinking 223 you can get pulled military bullets for around $45 per 500, this is also very cheap.
You will also need a set of calipers for measuring length.
I almost forgot if you dont buy a progressive press you will need a hand primer to seat primers.
Someone please add anything I forgot.
This is very addictive especially if you are chasing smaller group sizes.