Yes, mostly... Each city, municipality, county, state, etc has their own requirements and rules. You should have a chapter of the SBA or SBDC at your college or somewhere near you. Their advice is invaluable about what you will need. You can start at
The U.S. Small Business Administration | SBA.gov and go from there. As you narrow things down it will go down to the state level for you. They quite often give free or low cost classes for people such as you who are just venturing into business. The website alone is an amazing resource for a new business.
Don't depend on internet advice for much of anything. ANYONE can put ANYTHING on the internet and say it's the gospel truth. A consult with an attorney is always free. Consulting with an attorney can help you oodles without retaining him or her. There is also mention of legal aid thru your school, etc. I have no clue what's available there, but check.
You should seek an attorney's advice about this matter, but more so about the business stuff for your future clients. You need a good portrait contract. There are OODLES of them out there on the internet that you can use. It needs to cover everything you are promising the client and everything the client is responsible for. Then it needs to be reviewed by an attorney. You can never spell out too much in a contract. There may be parts of what you spell out that is overkill or unenforceable, but too much is never a bad thing. The usual: WHO WHAT WHEN WHERE HOW and WHY (or what for... $.)
You should also seek the advice of an accountant/CPA regarding your responsibilities for income, sales tax, record keeping, etc... Yea though you are reporting your income at this point, you probably aren't ACTUALLY making a profit and if you did things differently you would not be tax liable for that income. There are some things you need to consider and plan for in there, but a CPA can guide you along. It's tax time. If you haven't done your taxes from last year take them into any actual tax office and talk with the actual certified accountant there and he or she can guide you on what to set up for next year's.
You mentioned in your original post about prints and a printer-VERY few of us print our own prints. It's not cost effective. You need to use a GOOD, reputable, professional grade lab. The price of your prints does not only need to include the cost you pay, but it also needs to consider all of the other factors of cost of doing business and cost of goods-time invested, equipment, shipping, licensing, your taxes, sales tax... The list is pretty extensive. So a print that costs you $2 at the lab does not really cost you $2.
For example that $2 print: you had to take the shot, process the shot, show the client however you are showing (post to internet-and your internet service costs you...), you used your car to go there, computer to process, electric to run the computer to process, camera to take the shot... every one of those things cost you something. Even though you already own it. Your computer will get used up, your camera costs you somewhere around a penny for every shot you take-you do have to replace it eventually. You had to spend time getting the order and/or emailing the client, then placing the order, receiving the order, checking the order, delivering the order (which may require your car...) All of those things figure into the cost of that print. That is why the national average for an 8x10 is upwards of $25 per print.
You don't have a tax id yet, but there are many labs that won't require it: Mpix.com, WHCC, CPQ, BayPhoto... it's a LONG list, but those are all well loved. WHCC is probably the choice I see most new photogs go with and they seem to love it.
I have had several people and conversations about this start up business costs, pricing, etc questions lately and I really am working on a post about it. It's just that this is my busiest month of the year right now and I am literally balls to the wall running my butt off... I will definitely get there... I will try to remember your S/N when I get there! I am here daily and I have a few minutes to point you somewhere if you need it, but I don't have a ton of time like I usually do right now. Feel free to send a note if you have a question I might be able to point you towards a resource for.