As was discussed in another thread, some insurance companies let you choose whether to have it covered under medical as DME or under pharmacy benefits.
On my insurance it makes no difference from a cost perspective but I understand for many insurance plans it can make a substantial out of pocket cost difference.
Certainly worth checking for your own insurance plan.
EDIT: If your insurance will cover the Dexcom as pharmacy and if it is cheaper but your pharmacist does not know how to do it, the following Dexcom webpage may be helpful:
EDIT2: National Drug Codes (NDC)
Dexcom G5 Receiver Kit (Black), NDC: 08627-0080-11
Dexcom G5 Transmitter Kit, NDC: 08627-0014-01
Dexcom G5/G4 Sensor Kit (4 pk), NDC: 08627-0051-04
Dexcom G4 Transmitter Kit, NDC: 08627-0013-01
Dexcom G4 Receiver with Share (Black), NDC: 08627-0050-11
(It would be interesting for somebody to order the G4 Receiver with Share using the NDC under Pharmacy and report back if it turns out to actually be available.)