If it has NEVER had a bid (bids cancelled by you definitely count as having had a bid and any retracted by the bidder probably do) you can end early at any time with no fee.*
If you can't find a link to end that particular listing in your list of active listings (e.g. in your Seller Hub), Go to the Site Map (link at the bottom of this and most ebay.com pages) Sell Section (use the shortcut at the top--it's a long scroll down) and you'll find the link to that and several other useful seller tools.
*You don't get a refund of any insertion fees (e.g. optional upgrades such as a Reserve Price) you incurred when you set up the listing.
