Appears to be targeted, I received a unique code for this.
The offer entitles Eligible Customers to $5 off the purchase price (excluding postage costs) on all items listed on eBay.com.au, except the Excluded Items, when they spend $30 or more using the eBay App. A maximum of 1 transaction applies. Multiple items may be purchased in one transaction (up to a maximum of 10 items per transaction). All monetary amounts specified in these terms and conditions are in Australian dollars (AUD)
Did it come by email or app?