I'd be happy to answer your inquires about the subscription fee in QuickBooks Online (QBO).
In the UK version of QBO, there are different plans available that you can subscribe to, these are Simple Start, Essentials, and Plus. Each plan has its own features and pricing. And if you want to add payroll to your QBO account, you'll pay an additional fee. Your payroll subscription could either be Standard Payroll or Advanced Payroll.
As for the rates, it changes from time to time depends on the available offer. Thus, I suggest visiting this link: https://quickbooks.intuit.com/uk/pricing/. It contains the full product comparison with its pricing.
And if you're unsure about committing to a new version of QuickBooks, you can test out the products for 30 days. Just visit the site I've provided above. On the Pricing page, toggle the Free trial button to on.
Once done signing up, to familiarize yourself with the features available on your subscription, check out these help pages for a guide: