Topcashback have a promotion just now, if you join via my link you'll receive a £10 bonus when you've built up your first ten pounds of spending through them which is pretty easy to do.
There's no charge to join topcashback but make sure you go into account settings and select basic not premium membership once set up to avoid any charges later down the line. I do get a referral bonus if you use this link tia.
https://www.topcashback.co.uk/ref/charlotteclare Join topcashback for a ten pound bonus