I don't really identify with this article, mostly b/c it's talking about material goods, whereas the most I do with my friends lifestyle wise is play video games and go out to eat. But speaking as one of the wealthier friends, I think an easy lesson is if you value keeping your friends, don't be a cheapskate.

One of my friends just told me his wife is pregnant with kid #3, I'm not going to run a collections on his $25 worth of sushi, I'm honestly just happy to see his face once in a blue moon.