See, there are two common misconceptions that I've seen/heard from small and unknown companies and their sales people. Sometimes these misconceptions are repeated by (overly trusting) consumers making the misconception somehow an accepted fact.
1) Buy our product. It's better because we don't advertise and you will not pay inflated prices because of that.
This is simply not true. Data does not support it. In the senate hearing small and unknown companies *consistently* produced supplements loaded with contaminants. *Consistently*.
2) There are only a few labs in the world that manufacture these things. You are buying essentially the same product but just packaged differently.
That's another one you should watch for. While its true that there are several well establishing and well known quality labs out there, there are maaaaany bad ones too.
My rule of thumb, and I might be wrong on this, is that chem from EU and specifically from Germany and Canada is regulated and is usually good. Another thing I watch for is how long the company has been in business. Some small and well established companies don't advertise as much simply because they have been around for 20+ years. They have good quality stuff and their advertising is done by the quality of product and word of mouth.