I had a small 160L tank, cost about 1000 dollars. Kept spending money buying more zoas and palys before I realized the filefish was eating them - he never did it while I was watching and started about 3 months after having him. Cute little gobshite though. Isolated him in a temporary tank, but then aiptasia started growing. Filefish back, zoas got munched. Left the hobby now but I fear I might do it all again.
Just a tank and some lights, add some flow and boom! You’re there. Just get some salt and testing kits to keep things in balance. Those Hanna checkers are nice if you want to splurge - but that’s it, you’re done! I mean…. You have to get the fish and corals too - but you can make friends and get frags for free! Then you’re really done. Everything beyond that is automation, you don’t have to do any of it (although you can really dial in your nutrient balance if you use protein skimmer, algae scrubber, refugium, media reactors). But you don’t want to do that because then you’ll need a sump (but aren’t sumps handy? Who doesn’t want a sump?). Just make sure your stand accommodates everything-you don’t want to rebuild a stand. Leave room for controllers and uv meters and all that other stuff just in case you add it in the future - which you’re not going to becasue it’s expensive and overkill…