AITA for not buying my niece the PS5 she wanted even though my brother said I could?

I (32M) have a niece (17F) whom I’ve always gotten along with. For the past few years, she’s been expressing interest in gaming and has actually gotten pretty good. She asked me for a PlayStation 5 for her birthday this past weekend, and I told her I was sorry but I couldn’t afford it. <br><br>My brother called me an asshole and said I was being incredibly selfish and that I clearly have the money to buy her one since I’ve been dropping hundreds on the gym. <br><br>I workout because I havetraumatizing mental health issues and I work a job that requires me to be on my feet for ten hours a day. My brother doesn’t have these issues, and while I do spend a bit of money on gym membership every year, it’s helped me deal with a lot of the pain in my feet from work. <br><br>I feel like I shouldn’t have to spend hundreds of dollars on a gift for someone I barely see just to avoid being called an asshole.