On bedrock edition, lots of things cost minecoins. I was thinking that for a monthly subscription cost - you can gain access to loads of content without having to spend any minecoins. However, if your subscription ends - then you loose any content it included. The subscription would give you access to a wide range of marketplace content, and maybe even some content on featured servers. It would also give you free access to everything/most things in the skin editor. I'll let you decide the price, as you'll have to negotiate costs with everyone, but keeping the price below £10/mo is probably a good idea.