This is a great question, it is as much about understanding what is on the label as what is inside the bottle or jar. With good quality CBD, transparency is key, and knowledge is everything in order to get the most out of supplements of this nature.
So firstly, look out for what the plant has been grown in or with, check it is without the use of pesticides. The reason for this is that cannabis is a bio accumulator - meaning it is capable of absorbing both the good and the bad from the air, water, and soil in which it’s grown. If pesticides were used it's possible that they could be passed through to the CBD extract.
Next up is strength and efficacy, ensure there is a clear labelling on the concentration of CBD. The same goes for THC, there should be clear guidelines on the trace amounts of THC in the final product.
After this look into the extraction process. The cheapest and easiest ways to extract CBD oil commonly involves harsh solvents that can leave chemical residues (including butane, propane, and ethanol) in the CBD oil or balm. The best extraction method, and what we use here at KLORIS, is called Supercritical CO2 extraction which basically uses carbon dioxide (CO2) under high pressure and extremely low temperatures to pull out as much CBD as possible without the use of any chemicals.
Batch numbers and openness with regards to Lab Testing is also vital before feeling confident that a CBD product is a "good" one. At Kloris we publish all of our test results under each product online. We feel this is an essential part of our practice.
All of these factors will of course mean that "good" CBD has a higher price point than "bad" CBD but quality really is everything when it comes to CBD and plants in general.