Makes filling up that little bit less painful. Spotted this deal on the HotUKDeals site here, so credit to the OP there.
Get £5 off your tank of fuel with Shell Fill Up & Go when you pay for fuel with the Shell App. How to get this offer:
1) Tap 'Save Offer' and log in to your PayPal account when prompted. Link to save offer to your PayPal account: https://www.paypal.com/uk/webapps/mpp/offers?view=details&offerId=UDAXQWFW43Z64
2) Make sure you have downloaded the Shell App, registered for Fill Up & Go and linked your PayPal account to Fill Up & Go before visiting a Shell Service Station
3) Spend £5 or more on fuel at at Shell with Fill Up & Go, and pay with PayPal. Your credit will be automatically redeemed.
This offer is valid until 4,000 credits have been saved into customers’ PayPal accounts, whereby the offer will expire.