central office orders ours from moore medical, but that's for 7 schools. If you only need a pen and a jr pen for office stock, it may make more sense for you to get it from a local pharmacy or walmart pharmacy. They're expensive and expire quickly.
We have a local pharmacy that provides them to us for cost. We stock 1 Epi pen and 1 Jr. per school (12 buildings) and are able to get same-day replacement when needed. They make sure to provide pens with an expiration date of 1 year or more.