I want to highly recommend this conversation between Sam Harris and ethics philosopher William MacAskill.
It's long, at 2 hours so you might want to download the podcast to listen while you're doing something else.
They don't offer answers really but instead explore complicated ethical questions from many sides. For example, if you came across a child drowning in a swamp would it be alright not to save them because you didn't want to ruin your new suit you just spent $1,000 on? If not, would it then also not be alright to buy a luxury item when donating that money would save lives? How about spending money on space programs or arts programs? What if you were in a burning building and could only save one child and one of them was extremely bright and gifted and the rest were normal average children? Would you save the bright child? How about when there are limited resources to spend on medical treatments for kids, how would you feel about the hospitals using school records to give priority to the students with the best grades and highest IQs?
Lots of good food for thought.