If you signed up in 2018, before the full site launch, the registration is free. From then on (or, if you signed up after 2018) the subscription is only £25 per year.
All your content creation, use of the site, reviews, uploading of images, updating your profile, managing your calendar etc is free.
If you make a booking via the site, then there is a £10 booking cost, which will be deducted automatically from your fee by the escrow company, Transpact.
There is an additional fee of £2.99 to pay for the escrow service. This is payable directly to them.
If you add the £12.99 to your regular fee, then you have the whole service for free.