Regarding lower cost Viagra in Australia;
The manufacturer receives a much higher price than what the customer pays.
The following is outdated and prices are likely different now but it shows that in Australia, the government pays the largest slice of the cost.
The advertised price in the US is up in the $90 range ($US).
"CostFor the treatment of erectile dysfunction, Viagra comes in three doses (25, 50 and 100 milligrams) with four tablets per packet. The cost to the patient is the same regardless of the dose at $6.20 per packet.The Australian Pharmaceutical Benefits Scheme subsidises the drug; the cost to the government is between $54 to $82 per packet depending on the brand. Patients can expect to pay more if they buy Viagra over the internet."
https://www.sydney.edu.au/news-opinion/news/2016/05/13/the-hard-facts-on-viagra.html"Viagra costs an average of about $91 per pill"
https://www.healthline.com/health/viagra-price
(20min delay)