No, that’s not really the case. A "scam" would involve some sort of deceit. These are just free trials, (samples). Like a sample of a perfume or just trying something before you make the commitment to buying it or continue using it. Just about every diet pill website I've come across offers free samples, so it's not something new.
Of course weight loss comes from will power and proper exercise, but if you can find something that gives you a boost, then why not try it.
Nutrients comes from eating proper foods, but but it doesn't stop millions of people from buying vitamin C or E in the pharmacy section. None of which are ever FDA approved, but hardly anyone wonders, "If i buy this brand, will it kill me?"
However, this is the internet; your suspicions are completely justified. However, it’s not a scam.
For those of you who are interested

I can email you the details, if you feel its shady, then thats fine, if you find it even slightly appealing, then try it.