I've read through the long, long list of OP's posts.
She's unemployed, but that's not it. She can't afford to pay, but that's not it.
She's reduced her expectation from £10 gift vouchers to £5 gift vouchers to anything from a charity shop costing 99p.
What she will not back down is the expectation that people must bring her a gift - even though she's invited random strangers to her birthday celebration. And she knows only half of them from a Facebook group.
She will not accept that people turning up to help her celebrate her occasion is gift and kindness enough.
She will not accept good will and kindness as a lovely gift.
It must be something with a monetary value and given to her for the specific reason of her birthday, even if it is a stranger turning up to her social media post.
I think there is either a mental health vulnerability or a cultural ethnic minority difference. No one raised in Britain with traditions of giving out birthday cake to guests at birthday parties and giving out party bags - ever expects to just be given "stuff" from the wider public JUST BECAUSE it's their birthday.
In Britain we also either give something of value to our birthday guests (usually hosting/paying for a party), or we just value them for turning up to help celebrate our birthdays in their own time.
I'm still not sure whether OP is just nasty and entitled or vulnerable and ignorant.