I know what you mean, as everybody is capable of jealousy no matter where they're from - jealous of education, looks, money, social status, social skills, whatever.. However the kind of jealousy you experience feels extra bitter because they have (probably) done nothing to achieve these things, it's their parents hard work.
I am from a wealthy background and went to school with rich children basically all the way. Only difference is, I felt a bit the way you did. My parents are both well off but their wealth is mostly bound in properties, they have above average salaries but for many reasons they never had a high consumption (saving and investing well was how they got wealthy anyway). They are completely anti designer items and were quite strict with us growing up. We got quite a good allowance, but had to do a lot of work around the house for it. I agree with their attitudes a lot, although I think it was a bit extreme. I had 2 pairs of very cheap tights I wore everyday and some awful jumpers. I remember one morning I cried because I didn't want to go to school in the clothes I had - my tights literarly had holes on the inside on my thighs and my jumper was too small. Even now when I look back, I think it was ridiculous - we had 3 holiday resorts and I went to school like a homeless person.
I know they tried to give me a healthy attitude, but it didn't work out that way. Now that I'm older I've received a bit of inheritance and have had more to spend. I've kind of 'made up for' all those years, and splurged on designer clothes. If someone with less money sees me with a Chanel bag, they probably all think "spoilt bitch", there is no avoiding that.
OP, everyone feels jealousy sometimes. I can feel envy towards girls who look great, even though they don't have the most expensive clothes. They're just great at finding great outfits to compliment their figures.
If anything, try to direct your anger towards working. I don't mean to sound harsh, but sitting and moping won't change anything. It'll also make you a bitter person who's not pleasant to be around. I have plenty of friends who have money and are very nice (I'm a slightly introverted person, so my friends are all friendly - I'm not good at taking the first step to get to know people
so they have always been the ones to contact me ). Yes I know some spoilt girls whom are absolutely awful, but seriously no more than girls of 'lower' classes can be awful.