Hide Price by Role for a Content Type in Drupal 7
I have never used Drupal Commerce, however I understand that you want to hide a field according to a role. That is doable through hook_field_access().

hook_field_access($op, $field, $entity_type, $entity, $account)



  Determine whether the user has access to a given field. This hook is
  invoked from field_access() to let modules block access to operations
  on fields. If no module returns FALSE, the operation is allowed.


https://api.drupal.org/api/drupal/modules%21field%21field.api.php/function/hook_field_access/7