How much do you think is reasonable to spend on educational memberships for kids (e.g subscriptions to digital platforms, craft clubs or tech etc) per month?

We have two children that are 5/8 and haven’t got any subscriptions for them outside of the week for the elder one. I’m part of the PTA at school and they have mentioned putting out to the school WhatsApp an educational platform that gives back to schools. For each signup the school would receive £1 a month. It’s an invite only to schools but I’m a little reluctant to say yes and then have to sign up! It’s £7 a month and I don’t want other parents to feel like they have to part with this to support the school! I’m intrigued what others currently spend on memberships monthly! I don’t like signing up to subscriptions for the kids unless I think they are really worthwhile (although I signed up to the week because school recommended it and my elder one hates it) so wouldn’t ever want anyone to feel pushed- at the same time I’m the PTA so feel like I should support school! Any opinions on this so welcome!! Thank you!