Yes, ebay collects sales tax for any Marketplace state and remits it for you without your involvement. You do not pay this tax again yourself. However, different states have different requirements on how this amount is to be reported, so you want to check with your state's revenue office how it is to be shown, if at all, on your return.
Generally most states have you report gross sales, including ebay sales, but then have you include the ebay amount in the exempt total, since you are not require to pay the tax already remitted by ebay.
