I think she's mentioned parties twice now, but I'm sure they are close friends as they got tagged. Since starting school just over a year ago I think my child has had about 15 invites, the cost adds up though. We try and get a gift for about £10, for friends they've known for life we spend more. I can't imagine Robbo wanting to spend money on other children, to me I think of it as my child is being entertained for 2 hours with her friends, so I don't mind. Mind you I know some people who spend £2 on gifts and buy a colouring book and pens, not everyone spends the typical amount.
Also, when kids start going to other children's parties they end up asking for their own. Maybe that's why?
I can't imagine Ivy not being invited, she seems a sweet girl.