Depending on your local State some tax <may> be levied...
Buying online
If items of value <$A1,000 is purchased overseas and delivered to an Australian address 10% GST applies and is included in the eBay fees, however:
Items sold from Australia
If the item's located in Australia, the listing price is GST-inclusive, where applicable. Sellers may not add GST to the final sale price after an item has sold. If you need a tax invoice showing the GST component for an item you bought, please contact the seller.
Items delivered overseas
If you're having an order delivered to an address outside Australia, local consumer tax and/or customs duty may apply and the parcel's recipient may need to pay these as part of clearing the parcel through customs.
Items delivered to the US – sales tax
Tax laws vary between states, and sales tax may be required to be collected by the seller, collected by eBay, or paid directly by the buyer.
If the seller is located in the US and your delivery address is in one of the US states where either the seller or eBay is required to charge sales tax, the tax will be included in the order total at checkout.
If the item's being sent from outside the US, the recipient may have to pay duty and customs processing fees. However, items under $100 which are being sent as a gift will generally be cleared without any additional charges.
Paying tax on eBay purchases