Great comment @emmyem84! Yeah, even some easy filtering options would drastically improve the search results already or at least a way of excluding posts with certain characteristics (specific tags like you mention, or just filter out posts that have less than 100 characters of something).
On the promotion part an affiliate construction might work. Personally I am not always a fan of those since it is a 'push' incentive rather than a 'pull' incentive. But that is my opinion. Might work though!