An exclusive offer for all new and existing PS Plus members – sign up to Spotify Premium via your PS4 before 10th October 2018, and you’ll save 10% on the monthly subscription fee, for as long as you're subscribed.
Spotify for PS4 is required, as this is where you will add the billing details for the discount. Unfortunately it doesn't work for Family accounts (thanks jacro for confirming).
T&C:
Offer available from 10 April 2018 at 10:00 (GMT) to 10 October 2018 31 March 2018 at 10:00 (GMT). Offer entitles PlayStation Plus (“PS Plus”) members to a 10% discount on the recurring monthly subscription fees applicable from time to time for Spotify Premium (“Spotify”) memberships purchased from the PlayStation Store (“PS Store”) on PlayStation 4 prior to 10 October 2018 at 10:00 (GMT). To be eligible for this offer you must have a SEN account and be 18 years or older, and sign up for, or link an existing Spotify account in your name. Country restrictions apply. Offer not applicable to the purchase of Spotify from any platform other than the PS Store on PlayStation 4. Offer cannot be used in conjunction with any other discount or promotional offer for Spotify. If you cancel your PS Plus membership, your Spotify membership will continue but any future recurring monthly subscription fees payable for Spotify will be charged at the then current full price of Spotify as shown on the PS Store. PS Plus membership and the Spotify membership purchased from the PS Store will continue indefinitely until cancelled and the recurring monthly membership fee for each service will be deducted from your SEN account wallet automatically. Your use of Spotify is subject to Spotify's T&Cs: www.spotify.com/legal/end-user-agreement/.
I pay $3