Agile Rates
Agile Rates is a free, not-for-profit tool. If you are thinking of switching to Octopus Energy, the referral link below is the simplest way to support the site - it costs you nothing, and you get credit on your first bill.
Octopus supplies the Agile and Agile Outgoing tariffs this site tracks, so it is a natural fit if you follow those prices here.
Use my personal referral code when you sign up: rich-zebra-920
You'll get £50 free credit on your first bill, and I'll get £50 too.