Although it rhymes with poison, it's less about quality and more about quantity. 

Foison is a term meaning "over abundance." Or - the opposite of scarcity. 

Marketplaces with a surplus of inventory obviously are known for driving prices down. The trick is to differentiate your quantity to make them of higher quality - or at least to possess a unique value proposition.

Foison isn't poison, but without taking proper notice, it could be the death of your offering.