PrEP should be really cheap (~£10/mo) but the generic status of Truvada (emtricitabine and tenofovir) is being held up by legal shenanigans, so the NHS tariff price is currently £355.73/mo for the branded formulation. This has obviously severely constrained availability on the NHS, so a lot of at-risk individuals are just buying the generic online.
> It has been estimated that the average lifetime cost to the NHS for a person living with HIV is £360,000. Around two thirds (68%) of these costs were for anti-HIV drugs. The cost of a year’s HIV treatment is about £11,000 and of PrEP £5,000. The NHS obtains Truvada at a cost of £3,000–£4000 per person per year. People need to take HIV treatment for the rest of their lives but PrEP will generally be needed for a much shorter period. It is believed that the patent for one of the key drugs in Truvada, Tenofovir, expires in 2017, slashing the cost of the drug from this time. There has been a collective call on Gilead, from those involved in PrEP activism, to lower the price of Truvada for use in PrEP, as there are concerns that PrEP may not be deemed to be affordable.
$6000 for a 'one off' course of treatment sounds very expensive.
The NHS does not prescribe PEP long-term for anyone.
For HIV+ people, it prescribes HAART, which everyone who has HIV should be on.
HIV- people can take PrEP, which is different from PEP and does not include any NNRTIs.