When starting a business tax considerations are as follows. You will need an EIN that you can use for business income taxes as well as employment taxes. Then you need a state EIN if you will have employees. In addition, you need a state sales tax id if you sell tangible items or want to buy wholesale.
Even if you are a sole owner, you can use the EIN to do taxes for your business ( instead of your SS#). If you want to buy wholesale you need a wholesale ID also called a seller's permit or a state sales tax ID. The state ein is required if you have employees because you need to pay withholding taxes to the state and the the federal government.