> It does not have to be taken daily. You can take PrEP 'event driven', it is 'approved' this way by the WHO for MSM: https://www.who.int/hiv/pub/prep/211/en/

(Apparently event driven PrEP is indeed not approved or recommended for women.)

> Even in the West, isn't it really expensive?

One datapoint: In Belgium the out of pocket cost is 5 euros per package of 30 pills.