Under 'My eBay Plus' go to 'edit membership' and cancel. Follow the prompts and you should get a $30 Gift Card.
I chose too expensive, but I really wanted to say sellers jack the prices during percentage off sales!
I just did it today (28 Apr 22 for an account renewing on 4 May)
Its a $30 Ebay Gift Card ( not $30 voucher )
My payment hasn't gone through yet, so I can only assume it'll come through by email after mine renews.