Help buying on eBay: Can you explain the International buyer note about import duties/taxes?

I am a first time Ebay user, the item I’m interested in will ship from China and includes this note:

__Import duties,taxes and charges are not included in the item price or shipping charges.These charges are the buyer’s responsibility.__

__Please check with your country’s customs office to determine what these additional costs will be prior to bidding/buying__

Is the total (item price + shipping) on the review screen final? Can I be charged more later? I’m hesitant to hit the ‘commit to buy’ button because of this warning note.