One point in our current FAQ is that a shopping or buying recommendations are off-topic.
It is not uncommon for questions here to be about shopping or buying and we need to differentiate between "good" shopping questions and "bad" shopping questions.
I'll put some example questions in answers. My idea is that we should up-vote those that should be acceptable and down-vote those that should be banned.
I hope that after that, we'll be able to formulate some sort of policy on what are exactly good questions and what aren't. After that, we could refer new users to the policy instead of simply telling them that such type of questions is off-topic.