Hello Istluka,
1. yes you can hide the prices and only show this to registered and/or approved members. This would require a few theme modifications, to hide the prices for unregistered customers. A basic Liquid example is:
{% if customer and customer.tags contains 'approved' %}
pricing here
{% endif %}2. Technically everyone can sign up for an account, Shopify is aware of this issue (see the discussion on Accounts are required for these technical details). But it is still possible to protect your pricing using the above example. This requires manually approval of a customer before prices will be shown.
However unapproved customers still will be able to reach the checkout (where prices currently can't be hidden). You can hide the checkout buttons for unapproved customers to prevent checkout, although technically it is still possible to checkout.
HJ
