Links from other websites to yours were, for a long time, the dominant factor in search ranking. A whole industry grew up manufacturing them, and it still sells packages: five hundred links, one monthly fee, delivered in thirty days.
The mechanism it is exploiting has been under sustained attack for more than a decade. What you get now ranges from no effect to real damage.
What you are actually buying
Bought links come from a small number of predictable places. Networks of sites that exist only to host outbound links, often on expired domains bought for whatever standing they had. Comment sections and forum profiles filled automatically. Directories nobody uses that accept any submission. Paid guest posts on sites that publish anything.
These share obvious characteristics. The sites have no real audience. They link to hundreds of unrelated businesses. The pages exist for no reason except to carry links. Pattern-matching this at scale is exactly what search engines are good at.
Why it fails
The value of a link was always meant to be a proxy for a recommendation -- somebody found your page useful enough to point at it. Manufactured links carry no such information, and the manufacturing is detectable in the pattern.
At best they are discounted to nothing and you paid for nothing. At worst the pattern is treated as manipulation and your visibility is actively suppressed. Recovering from that is slower and more expensive than the links ever cost, because you have to identify and disavow them first, and you rarely get a full list from the seller.
There is also the abandonment problem. Link networks get shut down or expire. Whatever effect you bought disappears, so you are renting, which is why the packages are sold monthly.
The tell in the offer itself
Real link-earning cannot be promised by volume, because it depends on other people deciding to link. Anyone offering a guaranteed number per month is describing a manufacturing process, whatever language it is dressed in.
Watch for: a fixed number of links per month, a price per link, promises about domain authority scores, and vagueness about which sites the links will come from. If they will not tell you where the links are coming from before you buy, that is because you would not want them.
What actually earns links
Slower, and it holds.
Be genuinely useful about something specific. The pages that attract links are the ones that answer a question better than anything else available -- usually a narrow, practical question that a general publication would not bother with. If you know precisely what a licence costs and how long it takes because you do it every month, that page is worth linking to.
Be a real member of local business networks. Trade associations, chambers of commerce, professional bodies, supplier and partner directories. These links are legitimate, relevant, and they are also usually free with a membership you may already have.
Sponsor or supply something local. Schools, teams, events and community organisations list who supports them. These are real relationships that happen to produce links.
Get listed where your industry actually gets listed. Not every directory -- the two or three that people in your sector genuinely use.
Do work worth talking about. Suppliers, clients and partners mention who they work with. Ask a satisfied client whether they would be willing to mention the project. Many will, and it costs nothing.
The honest position
For a small business serving a local market, links are not the lever most worth pulling anyway. A well-maintained Google Business Profile, real reviews, and a handful of genuinely useful service pages will move local visibility much further than any link campaign, bought or earned.
Links matter most in competitive national markets where everyone has already done the basics well. If you have not done the basics well, buying links is paying to skip the part that would have worked.