Search for SAM.gov and the first results are rarely SAM.gov. They are companies with official-looking names and seals offering to "get you registered" for a few hundred dollars, sometimes more, often with a renewal charge every year after. Some of them are honest about being private companies. Many are not. All of them are selling something the federal government gives away.
What SAM.gov actually is
The System for Award Management is the federal government's free registration system. Every business that wants to be paid by a federal agency needs an active record in it. Registering assigns your Unique Entity ID, connects your business to your CAGE code, records your NAICS codes and size status, and lets you make the representations and certifications agencies rely on. It costs nothing to register and nothing to renew, and the renewal comes due every twelve months.
What the paid services do
They fill in the same free form, using your information, under a login they often control. The better ones do it competently. The worse ones make errors that follow your business for years, because the SAM record feeds your small business profile, your payment systems, and every proposal you submit. Either way, three things happen that hurt you: you pay for what is free, you learn nothing about a system you will have to maintain for as long as you sell to government, and someone else may hold the keys to your own registration.
How to tell a legitimate advisor from a look-alike
A legitimate advisor teaches you to complete and renew the registration yourself, under your own login, and charges for the teaching and the review, not for the registration. They tell you up front that SAM.gov is free. They explain what the record is for, walk through the parts that most often go wrong (entity validation, the notarized letter, NAICS choices, size representations), and check the finished record against your capability statement so a contracting officer sees the same business in both places. A look-alike charges for the form, is vague about who they are, and calls you every year when the renewal is due.
Keep it in your name
Your SAM.gov record is your business's federal identity. Create the account yourself, keep the login in your business's password manager, add a second administrator you trust, and put the renewal date on your calendar with a 60-day reminder. If someone else registered you in the past, log in, confirm the entity administrator is you, and remove anyone who should not be there.
If you want help doing it right, the Federal Contracting Foundations course walks through the registration with the system open on screen, and the readiness review checks a record you already hold. Neither of them will ever charge you to register.
Check the record you already have
The readiness review audits your SAM.gov record, profiles, and registrations and returns a prioritized list of fixes within five business days.