Have you tried eBay's Markdown Manager? My clients report having success with this free eBay tool, especially during weekends. When using Markdown Manager, sales can be run for any reason - to correspond with a holiday or season, to promote a type of item, or just to get rid of some inventory. There are two different types of discount sales that you can choose from on eBay - a free shipping discount or a price discount.
You can offer price discounts on your fixed price listings by taking off a certain amount (such as $3), or a certain percentage (such as 25%). Price discounts can be set for any percentage from 5% to 75%. The discounted price will be shown as the Buy it Now price in most places on eBay. There are a few places that the price will show as a sale price (with the regular price struck through and the discount shown) - in your listing, on cross promotions within listings, in search results (within your store), in the Watched Items section (in My eBay), in any reminder emails from Watched Items, in store promotion boxes, and in any email marketing messages you choose to send.
You cannot use a price discount with auctions. But, you can offer a free shipping discount on all listings - both auctions and fixed price. Free shipping discounts only work on the first type of U.S. shipping service you added when you created your listing. It won’t apply to any other shipping services you may have added.
Make sure you promote your sale as much as possible! Send a customized email to your Store’s newsletter subscribers announcing the sale. How many emails you can send and how often you can send them is determined by your subscription limits, as well as by eBay policies.
For more information on eBay's Markdown Manager, click here for a free tutorial.