It's a view shared by many, including myself. But not getting my lips done and going on a trip, wouldn't change the social structures that keep people poor, nor would the OP not getting something that she has wanted for over a year.
My mother would make snide comments about the odd expensive thing I would buy, my answer would be that I didn't know how she afforded to smoke/drink and go out every weekend.
Re @Birdsgottafly comments, we used to go on a few holidays abroad, including the USA and North Africa, (because we worked and saved,) and my cousin used to make snarky remarks about how 'it's all right for some!' Yet she smoked, (15 a day,) went to the pub twice a week, and had 16 pets (including 3 dogs.) 
And she didn't go out to work, and never had.
So she spent probably double the amount in a year on ciggies and booze than we spent on holidays, but she couldn't see that. Neither could my mother, as she asked me a couple of times if I could lend my cousin some money ('just a 100 or so,' she would say.... some 15 years ago,) towards her gas bill. I refused, and my mother was disappointed, and gave me a kind of 
look. Then she said it would be nice if people could help each other more!
It IS unjust by the way to say she is wrong to spend the money because other people have less than her. I usually find people who think people should share their 'wealth' a bit more, are the freeloaders, and the ones who want to live off other peoples hard work. Usually because they feel 'entitled' and a bit sniffy and resentful that others have seemingly been dealt a better hand in life than them. In most cases, it's just that the other person has worked harder and made better choices.