You have 50 CDs, all the same, that you'd like to sell for at least £5.99 each. You would list them as a quantity of 50, and a starting price of £5.99.

• Bidders specify both their offered price per unit, and the number of items they want.

• Winning bids are selected in order of bid price per item - that is, a bid for 5 units at £12 per unit is ranked above a bid for 10 units at £11 per unit.

• If two bids have the same price per item, the earlier bid is given priority. Winning bidders will pay a price equal to the lowest winning bid.

For a listing with 10 available items and 2 bidders:

• Bidder A bid for 8 items at £5 each.

• Bidder B bid for 3 items at £6 each.

In this case, the lowest successful bid is $5. So the outcome of this listing is:

• Bidder B wins 3 items at £5 each.

• Bidder A wins 7 items at £5 each.

• Bidders cannot lower their "total bid value" (the bid price per item times the number of items on which they're bidding) when they raise their bid in this type of auction-style listing.

• Winning bidders have the right to refuse partial quantities. This means that if you win some, but not all, of the quantity you bid for, you don't have to buy any of the items. In the above example, Bidder A bid on 8 items, but won only 7 of them. Bidder A can refuse to complete the purchase, because Bidder A did not win the quantity he or she bid on.

• Bids are displayed when you click on the link reading, "Bidders list". Bids that are not currently winning show their bid prices, but bids that are winning show the price that these bidders would pay if the auction ended immediately. This means that, in the Bid History, all winning bids show the same price per unit - the lowest winning bid. To place a winning bid (a bid that wins at least some units), a bidder would need to exceed this price.

You have 50 CDs that you'd like to sell for £5.99 each. You would list them as with a quantity of 50 and a price of £5.99. Buyers can purchase any available quantity of your item at any time, without waiting for the listing to end.

In Both Formats: eBay only permits multiple item listings in which the price times the quantity is less than £60,000.

Note: to sell with this auction format, you must be a registered member of eBay for at least 14 days and

• Have a Direct Debit on file for payment of eBay fees, or

• Have a feedback rating of at least 20, or

• If you have a PayPal account linked to your eBay account, have a feedback rating of at least 10.

• Sellers must list a minimum opening bid of at least 99p or EUR 1.00.

You have 50 CDs that you'd like to sell together to one buyer for an average price of £5.99 each.

To list these CDs as a "lot" you would first click the Lot tab in the Quantity section of the Sell Your Item form and enter "1" in the Number of Lots box and "50" in the Number of Items Per Lot box. You would set the price to £299.50. The winning bidder will win all 50 CDs.