The version that does work is smaller than the term suggests. Somebody with a modest local following who genuinely serves the same people you do, paid or gifted, mentioning you because they actually used the thing. That is closer to a referral partnership than a campaign, it costs little, and the trust transfers because the audience knows the person is local and has something to lose by recommending badly.
What fails is the version with a media kit. Follower counts are a poor proxy for influence, are trivially inflated, and correlate weakly with whether anybody acts. If you evaluate anybody, look at comments rather than followers: whether real people are having conversations, whether the same names recur, and whether previous promotions produced any visible response. An account with high followers and silent posts is an audience that scrolled past.
The legal requirement is not optional and it is enforced. Any material connection, including payment, free product, or a discount, must be disclosed clearly by the person promoting you. That responsibility sits with them and the exposure extends to you, so it belongs in whatever you agree in writing. Undisclosed promotion is the kind of thing that becomes a story rather than a fine, which for a small business is the worse outcome.
Structure it to be measurable or do not do it. A unique discount code or a dedicated link means you know what it produced. A general mention with no mechanism produces a number you cannot attribute and an argument about whether it worked. If somebody resists a trackable mechanism, that tells you something about their expectations of the result.
For most first year businesses, the same budget spent on reviews, a referral habit, and search visibility produces more, because those compound and an influencer post does not. Revisit when you have something visually distinctive, a product that photographs well, or a genuine relationship with somebody whose audience is your audience.
If you do proceed, agree what happens to the material afterward before anything is posted. Whether you may reuse the photographs or video on your own site and in your advertising, and for how long, is a question that arises later and is awkward to raise retrospectively. Creators own what they produce unless the agreement says otherwise, which means the content you paid to have made may not be content you can use anywhere else, and that is worth settling in a sentence at the outset.