I'm not sure if silica packets are sold separately in stores (I'm thinking you'd have to go online for some, like Amazon) but I know they also typically come in things like jewelry boxes, display cabinets, sometimes even in dry food packages, and things like this. Personally, I think even if you do live in a dry climate, it'd be nice to have silica packets for your collection box anyway, as silica is a really good desiccator and dehumidifier, so it'll help keep a lot of moisture away from your Tamagotchis, even though you may not see or feel it.