I'm going to keep the xmas gift I got for my friend
Why are you keeping the gift?
I bought it because I saw it and it looked cool. I should buy him something cheaper
Keeping something you initially bought as a gift for yourself and replacing it with something cheaper is quite mean. You should give your friend the gift you initially bough for them.
Hey, it's my decision you know. I can do whatever I want with something I bought.
It is your right, but I don't think you should be this rude to your friend. If you initially bought the gift for your friend then you should give it to him.