Here are some links for you to review:

https://www.state.nj.us/treasury/rev...ing/leadpg.htm
http://www.state.nj.us/treasury/taxa.../sales/su5.pdf
http://www.state.nj.us/treasury/taxa.../sales/su4.pdf

You'll need to register with the state to collect sales tax and file your payment on a semi-annual basis. You're only responsible for collecting on internet sales shipped to New Jersey.

You'll probably want to incorporate, to add a little protection to your company but also to establish your company as separate from you .... some suppliers may unfairly judge you guys on your age. First you'll want to apply for a employer id number (EIN) which is like a social security number for your company. You'll receive payroll reporting forms, but you'll only need to file once a year ... probably $0 withheld because you'll both be taking from the profits.

Sounds like a lot, but it's not. Just turn a profit and fill out forms, those are the important details.

Good luck.