Have buyers return daily. No inventory.
Every day the store offers many kinds of items. Each item is on sale for only that day or until it runs out during that day. The next day’s offering is entirely different and does not include any of last day’s offering.
Help convert the ones who are just a step before buying.
When a visitor seems to be interested in an item (he spent more than average time on that page, scrolling back and forward reading, etc.), but then seemed to not buy the item and move on to something else (still on your website), you can pop up a one time offer that has a very short time limit (one minute should be more than enough.) It might say something like this: “Get XYZ for $79 instead of the usual $139 price. This offer is only good if you add it to your cart within the next 00:48 seconds.” (The time is an active countdown.) Once it’s in the cart, it should have a small text saying that the discount is only valid if they buy it during their current visit. This will help keep them from abandoning the cart and not finishing the purchase.
Bring old and new customers in, and provide a fun, social and useful experience.
Have a separate room dedicated to the sale. Only allow a set number of people to go inside at a time. Next person can go in when another one comes out. People have to register in advance. People go inside in registration order. Each person has a time limit on the stay inside. They get a wristband that will beep when time is up. Payment for the goods happens inside.