Check your EBay inbox to see if you have the offer. It has been a long while since the last time EBay offered this.
What is the promotion?
Pay no insertion fees and $1 in Final Value Fees per listing on up to 10 items you list and make available for purchase in Auction-style or Fixed Price format on eBay.com.au during the Promotion Period (see exclusions below).
Insertion Fees are the fees to list your item, and Final Value Fees are the selling fees charged on sale of an item, calculated as a percentage of your total sale price.
Got a similar deal last month and sold a bunch of stuff lying around the house! Just remember to read the T&Cs carefully - one of them I got caught on was "Single quantity items only". I listed an item as having '2 in stock' and was charged Final Value Fees for both (luckily Ebay customer support gave me a one-off refund)