The cost of this project includes $28 for buying the insulin autoinjector at retail. There is no way it costs $30 to manufacture. I'd be amazed if they cost $5.

The cost of this project includes $28 for buying the insulin autoinjector at retail. There is no way it costs $30 to manufacture. I'd be amazed if they cost $5. Injection moulded plastic is extremely cheap once you've made the moulds.