Things add up quickly. For size, your chores really do not get very different unless you get past the 4' length or 120 gallon range. So at 4', you have 70, 90 or 120 gallon. There are also 6' aquariums in 125 or 150.
You need the aquarium, the stand, the plumbing, the sump, the protein skimmer, the return pump, power heads for circulation, a quarantine tank, a return pump, an rodi unit, tubs for mixing water, and lights. If ou want to keep photosynthetic corals, and most people do, you need really, really powerful lights. Lights will be one of your major outlays. Also, you need rock, either dry or live and that s another major outlay.
I would suggest the 4' 120 or either of the 6' tanks. A tank at the 120 gallon range gives you far more options for fish. But all of this comes at a price.
This is not an inexpensive hobby. Some people do it on a modest budget but they rely on DIY and expertise. A neophyte is not likely to have either.
Even people who have pot loads of money can fail. A good reefer had to be patient. So it comes down to time, money and expertise.