I think with young girls this comes from them being in a household that doesn’t believe periods are important enough to spend any money on tampons and pads.Also UO and the similar to what you said is period poverty.
I just can't work that out when you can buy a pack of own brand pads for less than a pound, or a branded double pack for a pound in shops like Savers.
Don’t get me started on some pretentious Instagramer saying that Diva cups etc are a better solution for period poverty and more environmentally friendly. I’m 30 and I wouldn’t feel comfortable using a diva cup et al so I doubt a teenager who is already struggling with getting their hands on sanitary products would feel comfortable either.