This dataset includes results of double blind field experiments and experimental auctions conducted with bean farmers in Tanzania to gauge the relative demand for four types of seed products--i.e., certified 1, certified 2, quality declared, and recycled seed. Files include data on: a) farmer rating of the four seed quality types planted in the farmer managed field demonstration plots; b) farmer’s bid on these four seed quality types during the seed auction experiments conducted on the second field day before harvest; c) farmer survey data; and d) field experiment yield data.