hmmm... its a tough place to be for a parent... like you said, they have to choose between giving some slack their child as far as having things that help them fit in, and also teaching them to be more self-sufficient, and not fall into peer pressures...

Since i don't have children, all i can remember is myself being that age, and now that i think about it, my parents actually did something kinda clever... they were much more favorable to let me have things that I wanted because I thought the item was unique, and really never got me things that i wanted because everyone else has them... so i had developed a taste for unique things... and even today i'm turned off by trends and brands... Thrifting is all the rage! haha.

I also like your idea of splitting the cost with the child. This can be a positive experience and reinforcement on many levels.