This article describes low-cost well plates that can be used as alternative kits for microscale experiments. Although ordinary well plates are useful and convenient for microscale experiments, they are not cheap. We have developed well plates composed of plastic bottle caps with approximately 3cm diameter and cardboard containers. Plastic bottle caps are capable of holding many chemicals, and they resist concentrated aqueous acidic, basic and salt solutions. Their containers are made from cardboard (0.45mm in thickness), and the production cost per container is 1/60 to 1/45 of the price of an ordinary 12-well plastic plate. Moreover, both plastic bottle caps and cardboard containers are reusable.