Options: 

1) 'How other people spend their money isn't our business, we should put our energy into other things that really matter to us.'

2) 'I know it's hard not to have the nice things you want, but we are so lucky to have family we love, and a warm home. Whenever we feel envious of others, we should refocus onto how grateful we are.'

3) 'Lots of people get nice, fancy things from their parents, but that doesn't mean that they're lucky. How much time, love, and attention do they get from their parents? We don't know, so we shouldn't be jealous when we don't know why material things seem to be so important in that family. Expensive stuff doesn't not equal happiness. I wonder how long a new iPad makes your friend happy before that feeling wears off and it doesn't make them happy anymore.'

4) 'You never know what other people's finances are like. People may have everything they want to buy, but for all we know, they don't have savings, they're going without healthy food, holidays and experiences, or even getting into debt to satisfy themselves in the short term. In our house, we prioritise owning our home so we can have a nice place to live that's all ours, and memorable experiences that will make us happy for a long time, and saving for your and our future. And being debt free, so we don't have that kind of stress. Just because people have the nice things doesn't mean they're happy, stable or going to be able to afford things forever. Most people don't have it both ways. Financial management is important and we will continue to teach you about it of you want, so you can understand how money works, especially in different classes in the UK.'

Depends what you want to prioritise in terms of parenting, and depends on what your kid is like, maturity and interests etc. It's an opportunity to teach her not to compare herself to others, not to put too much value on material goods, not to judge others, and to learn about the class system and personal finance.