Clicked on a banner to this page, not sure if it's targeted but it does say 'eligible users'. Voucher is valid for 30 days.
If you are an Eligible User and take up the Offer, you may sign up to the Offer by:
clicking on the promotional banner on ebay.com.au or a link found in the offer email; and
signing up for an eBay Plus membership through the sign-up flow https://www.ebay.com.au/ebayplus/subscription/signup?promo=PLUS50CPN