I know its hard to guess, but what would you say is the minimum yearly salary one would need to live alone in a small apartment?

It depends entirely on the location.

Your monthly income MUST be 3-4 times MORE than the monthly rental amount.

Go open the newspaper and look at the classifieds for apartments. Find a one bedroom that is the are you would live in. Multiply that number by 3 then again by 12 (months) which will give you the minimum yearly salary necessary.

Depends where you live and how nice you want your apartment to be

it is dependent on location. the cheapest apartment rent near me is 1300 a month and they require you make 3.5 the amount of rent so my minimum salary to stay comfortable would be around 60k. some places are just expensive to live.

that depends on what your rent is
if you don't make 4 times the rent, forget it

Where I live you can live very frugally on about $1000 a month (take home)

Not knowing what your life style is or your food likes and dislikes are, I can only tell you that your
monthly wage needs to be 3 times the monthly rent.
Therefore you should calculate your cost for all else. If you maintain a car & insurance that is another concern.

It depends entirely on the location..

Your monthly average income should be 2-3x the amount of the rent. If the rent is very cheap, $15,000 may be enough annually.

Depends on where you are.

around 16,000 if you live VERY frugally and in an inexpensive part of the country

We have to know the state and city

Depends if you get welfare like food stamps and EITC. People on SS sometimes live on just that maybe 1,000 a month but they get lots of welfare like food stamps, low income housing with vans for transportation and Medicare.

A child leaving home will need more income unless they have parents providing transportation, phone and medical and inviting them to dinner several days a week.

Rent seems like the biggest expense and all expenses vary greatly by person and location. Where I am the average rent is 2K but some find it cheaper than average so you might find 1,500. Medical is the most variable without Medicaid or Medicare you will pay a few hundred to a few thousand. A car is the next expense if you try to keep one you need to budget gas, oil, repairs, license and replacement cost so depends how nice you want and the amount you drive. Getting just housing medical and transportation can cost you 3K a month before utilities, food and wants like entertainment, cell phone, internet, etc. So I would try for at least 5K a month unless you find much cheaper housing and medical or live without a car.