Yes, you can but there are also websites you can do so through as well. I recommend PanterraPets and MantidKingdom for mantises! Please do your research and make sure to purchase a beginner species so you can gain experience. You will also need to research the foods mantises eat and properly gutloading them as well. TheMantisPlace is a good place to purchase feeder insects such as houseflies and bottleflies for when your nymphs are bigger.