I'm with Octopus Energy & they're currently offering £50 credit for new customers. I will also receive £50 credit.
Ref link: share.octopus.energy/maize-whale-356
If you have already joined without a ref link, you can simply copy and paste my ref link, go to the referral section in your dashboard (at the bottom). There should be a box for you to paste it into.
Octopus is currently cheaper then most suppliers. This is because they did not pass on a standing charge increase in Janurary, unlike most of the other suppliers