No, that's not normal. It breeds resentment, and ill feeling, as you are discovering.
'Your dress is nice - where did you get it from?'- 'River Island - £x' - is that not normal between good friends?
Nope. I'd just say, "River Island." I might mention if it was in the sale, or if I thought it was a bargain, but I still wouldn't give the exact price.
'X got me this bracelet for my birthday - 'cannot believe he paid £800, I think it looks awful'
Absolutely not. I wouldn't tell a friend that X had spent £800 on my present; neither would I say to a third party that I thought it was awful - sounds ungrateful and might get back to X.
'Y wants some new trainers - he has outgrown his ones already - bloody Jordans are over £200!'
I would only say this in the context of, "so he's certainly not getting Jordans". TBH if I told a friend I was spending £200 on a child's trainers (or my trainers come to that) they'd think I'd lost the plot.