The cheapest streaming services are the ones that come free. That could be services like My5 and Channel 4, which depend on ads to stream free content. The BBC iPlayer counts as well if you already have a TV licence on hand. Now, if you're already subscribed to these, the next cheapest options are those that don't go beyond the £10 monthly price point. That would mean a lot of on-demand streaming services like Britbox (£5.99) and Apple TV+ (£6.99) as well as affordable live TV streamers like Discovery+ (£3.99) and Now (£9.99 for the entertainment pass).
Below is a full list of the cheapest streaming services in the UK, as well as relevant details about each one of them.