Sadly reef aquaria end up being pricey. How much budget do you want to spend, 250 ish?
How big are 3 feet long tanks where you live (try to get a decent one or second hand) - I like 3 feet as a 'economy size'.
Do you need to buy a stand?
Do you live in a large metropolitan area? Do you have anything like a heater, HOB filters, powerheads and so on.
If you read the sticky at the top called my new tank or something likethat, that is about a 30 gallon I setup a couple years ago (and which still runs in some form) with the emphasis on economy.
If you want a heavily stocked reef 250 is not going to get you there. However if you can deal with low stocking, and are comfortable with thinking about what you're doing I think a FOWLR tank with a few fish and some inverts is actually possible.
tank
hood
lights
water
salt
test kits
hydrometer
HOB filter/cannister
powerheads
live rock.
That's a very basic shopping list. I have a very basic 20 long in my basement that is probably the most basic tank in the world, you can do better than that. That tank is also surprisingly successful.