I can speak only for the Amazon Vine program: one does not apply. Based on unknown metrics an invitation to participate shows up one day. Presumably the invitation is based on a history of quality Amazon product reviews. But this is just a guess. It could be because Jeff and I have a degree from the same institution of higher learning. It could be because Alexa likes me. Who knows?
At any given time a Vine reviewer is presented with a small selection of Amazon products to order. At the moment 12,999 -- 6162 of which are in the category "Kitchen and Dining". Almost always these are products from third party Amazon sellers, but occasionally the products are items sold by, as well as shipped from, Amazon. I can order up to eight products per day. Some days my doorway is blocked by boxes.
In addition to items in the kitchen category, I shamelessly adapt industrial and scientific devices for my culinary projects. Today I ordered two more centrifuges.
