Insurance cost could approach $2000 depending on coverage required.
You do not need to be licensed to operate a detailing business in the State of NJ. However, you will need to register your business name with your county clerks office. They will in-turn forward your info to the state in order for you to get your NJ Sales Tax Forms.
Tax prep is really up to you. Basically, it's up to you to keep a journal of your income and expenses. Then you will need to send in your sales tax collected quarterly. And send in your quarterly estimated taxes too.
I hope this helps...
p.s. 1- Have you given any thought to taking a few of those 'Start Your Own Business' courses? That's what I did when I started my own detailing business. I attended Rutgers here in South Jersey. You may want to look into that possibility. 2- Have you given any thought to writing a business plan? That's always a good idea, especially when it comes to just writing down your thoughts and ideas. It's a good way to set some basic goals and business objectives. Well worth your time.