You can fight against results - lying in advertising by saying that your Patented Snake Oil Tincture cures everything really does "work" and bring in money, but it was stopped by regulation; lying that this knock-off is really SuperBrandItem does work and bring results, but trademark laws significantly reduced it; selling things that look ok but break immediately are solved by various warranty and fit-for-purpose laws, etc, etc.
This is fundamentally a coordination problem that can't really be solved by individual users separately "voting with their wallets" (as past experience shows - none of the problems listed above were solved by consumer choices) but can be solved by coordinated requirements, with the users as a community voting in standards and regulations for commerce that are mandatory for every seller.