I get the impression the "voucher/gift" was a BOGOFF. That is, the friend qualified for a free spa day only if she brought someone along with her who paid.
It's like "A" visiting a friend (B) and saying: "Hey B, let's go and buy some wine and have a lovely evening at home."
"Sure," says B, and they go to the supermarket.
At the till, B pays for wine. A was given a BOGOFF voucher as a present (shit present, btw) and walks through till area clutching "free" bottle of wine.
A then walks off in opposite direction from B, explaining that she had a BOGOFF voucher as a present, so "her" wine is free, though B's wasn't.
In fact, A's wine was dependent on the purchase of one bottle + voucher, so the price should have been halved between them.
OP - She is well cheeky. If you decide against dumping her, be aware that she is like this, and keep her in view - behaviour-wise. Just don't put yourelf in a position where she an pull these sort of stunts.
I have a friend like this. I think it is, genuinely, a MH issue in her case. A few of us have noticed her behaviour and we have swapped notes occasionally. I love her to bits, and so I put up with it, and just try to avoid situations where any money is involved. But it is tricky.
Good luck with your counselling. Life is a process, ongoing, full of change: cliche for sure, but also true. Well done for committing yourself to changing things that inhibit your joy in life and for moving towards greater fullness and happiness.