Monzo has a great introductory offer at the moment. Their standard reward is £10 for new sign ups, but right now you can get £20 or £50 as well (it's random). How to get it:
- Sign up using a referral link: https://join.monzo.com/c/075svpm
- Make any debit card payment within 30 days. It can be topping up your phone, adding to Amazon balance, any payment works.
- Claim your mystery reward (good luck!)
- Refer spouses, family or friends and you both get rewards. My spouse signed up and we got the £20 reward.
I originally signed up to Monzo for the welcome reward but found it very useful to have as a second account, they have some great features and their savings account actually pays more interest than the one I had with my main bank. I think it's worth keeping it even after getting the rewards.