I've been through the full FCC certification process for an intentional transmitter, and it is pretty labyrinthine, on top of being very expensive (I recall $30

I've been through the full FCC certification process for an intentional transmitter, and it is pretty labyrinthine, on top of being very expensive (I recall $30k, but I don't have access to that company's financials anymore). Its certainly true that a module can save you a lot of money for small volumes. Its actually pretty easy to figure out where the tipping point is: Its the difference in certification costs divided by the difference in BOM costs. Its a little bit more complicated when you factor in economies of scale, but by and large, module costs don't fall off as steeply as individual components do.