This is old, I know, but I still want to answer.
I would sit down & have a real talk with my kids about the inequities in life & that is simply one of those things. Some people are born with more abilities than other. Some are brilliant, some gorgeous, some are incredibly talented, some have major health issues right from the start, this is life. And the same happens in how much money various people have to buy superfluous items as well as how much time someone has in the day to spend with you, etc. There are kids who get their parents with them all the time, some seldom see their parents at all. Some kids are super tall, some very short, some wealthy, some wear all hand me downs. This is life.
I actually like opportunities for my children to witness obvious inequities. Life is full of them. Learning to be happy despite those inequities is a major life lesson most of us will have to learn because most of us will not be born into incredibly wealthy families where we are gorgeous & riding the top of the social wave all our lives. I point out people near & dear to us that have been given the bad deal in life, like a close relative with a severely debilitating disease. They need to understand there are worse things than not getting all the toys you want. I also show them children that live in seriously tough conditions, like refugee camps and then I get my children involved in saving money & raising money to go to relief work for people who have it much much worse than we do. The ongoing fundraising helps them remember their own blessings & that someone, somewhere else, thinks they are incredibly lucky & is jealous of all that they have.
Life really is not fair. It's not. People who want children desperately sometimes cannot seem to get there. Others do not want children at all & end up with unplanned pregnancies. Some work very very had every day with little reward or pay & others hardly lift a finger & make a lot of money. Some live terribly unhealthy lifestyles & live to be in their 90s, while others do everything they can to live well and die young. This is how it is. The younger you start to actually learn how to accept this as fact, the better, because it isn't going to change. I have a son who was recently complaining about his BFF's new headset (very expensive one) and so I said, "I think I can help you". We are currently saving up for a clean water project for people that have to walk to get water. So I had us each grab a gallon milk jug, we filled it with water, and walked one mile. He wasn't thrilled about it initially at all. We did that every day for one week & then had a real talk about how some people are doing that every single day of their lives or they do not drink, can't cook, can't live. And we only did one gallon and only for 1 week & it wasn't a good time. I haven't heard another word about the headset.
I am a firm believer that my children's real happiness in life long term will never be dictated by the things I have bought them. I will never feel guilty about what they do not have or worry about what someone else does have. That isn't what makes or breaks your enjoyment in life, it's what you have happening inside. You can have nothing & be full of joy & have it all and feel empty. Fill your boys up inside & what they do or don't own won't even matter.