Congratulations on earning a great income. However, you have a lot of debt and very high living expenses. This will eat all of your income if you don't get a hold of it now. I have a few recommendations for you.
- Learn how to make a monthly budget, and commit to never again spending money that you don't have.
At the beginning of each month, write down your income, and write down all your expenses for the month. Include everything: rent, food, utilities, entertainment, transportation, loan payments, etc. After you've made this plan for the month, don't spend any money that's not in the plan. You are allowed to change the plan, but you can't spend more than your income. Budgeting software, such as YNAB, will make this easier.
- Treat your debt like an emergency.
You are $51,000 in debt. That is a lot. A large portion of your monthly budget is loan payments. I recommend that you knock those out as fast as possible. The interest on these loans makes the debt continue to grow the longer you hold them, which means that if you take your time paying these off, you'll be spending much more than $51k on your debt. Minimize that number and get rid of them as fast as possible.
- Cut your spending to the bare minimum.
Because you want to get rid of the debt emergency as fast as possible, you should reduce your spending as much as you can and pay as much as you can toward the debt. Pay off that furniture first (the interest rate on that "free money" is going to skyrocket the first time you are late with a payment), then attack the student loans. Stay home and cook your own meals as much as possible. You may want to consider moving someplace cheaper. The rent you are paying is not out of line with your income, but New York is a very expensive place to live in general. Moving might help you reduce your expenses.
- Don't ever spend money that you don't already have again.
I hope you realize at this point that it was pretty silly of you to borrow $4k for a new bedroom set while you were $47k in debt. You referred to your low-interest loans as "free money," but they really aren't. They all need to be paid back. Ask yourself: If you had forced yourself to save up $4k before buying the furniture, would you still have purchased the furniture, or would you have instead bought a used set on Craigslist for $200? This is the reason that furniture stores offer 0% interest loans. They got you to buy something that you couldn't afford. Don't take the bait again.
You didn't mention credit cards, so I hope that means that you don't owe any money on credit cards. If you do, then you need to start thinking of that as debt, and add that to your debt emergency. If you do use a credit card, commit to only charging what you already have in the bank and paying off the card in full every month. YNAB can make this easier.
- Salary or contractor?
$50/hr and $90k per year are fairly close to each other when you factor in vacation and holidays. That is not including other benefits, so any other benefits put the salaried position ahead. You said that you have a few more years on your parents' health coverage, but there is no need to wait until the last minute to get your own coverage. Health insurance is a huge benefit. Also, in general, I would say that salaried positions have better job security. (This is no guarantee, of course. Anyone can get laid off. But, as a contractor, they could tell you not to come in tomorrow, and you'd be done. Salaried employees are usually given notice, severance pay, etc.) if I were you, I would take the salaried position.
- Investing for the future.
Investing is important, but so is eliminating this debt emergency. If you take the salaried position, one of your new benefits will be a retirement program. You can take advantage of that, especially if the company is kicking in some money. (This actually is "free money.") But in my opinion, if you treat the debt as an emergency and commit to eliminating it as fast as possible, you should minimize your investing at this point, if it helps you get out of debt faster. After you get out of debt, investing should be one of your major goals.
- Now is the time.
Now, while you are young and have few commitments, is the best time to learn to live on a budget and eliminate your debt. This will set you up for success in the future.