This seems like a really bad idea.
Like any product - there are probably a lot of cheap, low quality suppliers out there that will sell you a product if you don’t know anything about how to evaluate the quality of the product - which could be really bad for you and anyone else buying it.
What type of quality control are you doing on it? In the USA and especially in some markets like California all food type products and supplements have to be tested and guaranteed not to have any significant levels of heavy metals and other chemicals that can be really bad for you.
For a few extra dollars a month - I think you want to buy the proven higher quality products that are more likely to be available already in the market.
While BrainVitaminz.com is an advertiser here - so we are slightly biased, we only allow advertisers on here that we feel comfortable with as providing a quality to our visitors. The company is owned by a PHD researcher who does testing and validation on all the quality of the products they sell. Similarly the company Profrontal is sold by, is also owned and run by an MD who completed his work at UCLA. Both those companies I would trust. I would only trust a company that is likely to provide a quality product to you.