Do I have to charge sales taxes on items I sell online?
It depends on the state you are in. If you do need to collect sales tax, it is only on goods shipped within the same state. The problem is that this can make you less competitive, so some sellers get around it by setting up a mailing address in Nevada. eBay has its own tax table but recommends you speak to an expert Link hidden: Login to view.
Regarding a sales permit - it depends on your state. The best idea is to ring your local tax offer and they will be able to tell you what you need to do.
You don't need a tax ID unless you are ordering from a wholesale supplier that requires it (whether or not a supplier requires a tax ID is shown in the supplier details). Usually the only suppliers that require a tax ID are based in the US and require large MOQs. A tax ID is easy to get from your local tax office. Give them a ring and they will tell you what forms you can fill in - sometimes you can do it over the phone.
Is an EIN the same as a tax ID?
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No - an EIN is only required if you have employees or are a business entity. A EIN is federal, a tax ID is local.
Should I just get a DBA for my business name or LLC?
It really depends on how you wish to run your business. Many eBay businesses run as a sole proprietorship which has a lot of advantages while the business is still small - especially if being run from home. However, a LLC protects you personally. I wouldn't think a DBA would be necessary - these are usually used for franchises. However, you really need to discuss this with a lawyer as the best option can be very subjective.