Fortunately insulin is dispensed in lots of 25 (ampoules or pens) 3 mls of 100 units insulin. It costs me AUD 46 each time (cost to Govt quoted as $469) with 1 repeat and lasts me about 90 days each script.
25?! I get mine in boxes of 5, which with a 3ml pen cartridge lasting 1-2 weeks (basal longer, bolus shorter) works pretty well.
Dispensing singles seems like a nonsense though.