yes, I thought that poster had a bit of an misogynistic overreaction. The friend's behaviour isn't great but we don't know the full story.
Is there any way you can plan in advance to do things a bit cheaper, OP? e.g. I noticed you mentioned 'odeon tickets are £12/14' but there are 2 for £10 deals on amazon, similar deals on wowcher, 2 for 1 with meerkat, the only by me does £5 mondays, etc.
Same with a meal out - if you go outside the weekend and/or use a voucher you can get a meal somewhere nice for the same price as a spoons.
Of course you shouldn't always have to 'do' stuff to meet up with friends, and if my friend was struggling so much I'd cover them if I really wanted to do something they couldn't afford, but it's understandable that if (like most of us) she only has a certain amount of free time and lots of stuff she wants to do, that if she has other people who would also like to do some of the stuff, she spends it with them sometimes.
e.g. if she really wants to see X film, and her only day free is Monday, and you
initially agree to meet up and see it, but then say you can't afford it, it's fair enough for her to think she'd rather spend the time doing the thing she wants to do, either with a different friend or alone, as that way 2 birds 1 stone - catch up with a friend AND do the thing.
Obviously if she had previously agreed to meet up with you for a walk and then cancelled in favour of a better offer that would be rude, but from your post it sounds as though you're the one changing the agreed outing rather than her.