Looks to be targeted - offers include $20 which is the same as this deal, $40, $50 or $60 gift cards.
Accept Offer via the email, sign up to Plus for $49, Receive your $60 Gift Card.
So for those that are not currently members or might have cancelled recently, keep an eye out for the offer
They are actually paying you to become a member now ;)
Copy of the image in the email below:
*Offer ends 30/9. No Free Trial. Not valid with any other eBay Plus signup offer. T&Cs apply.