Me personal opinion is that if you can afford $3,000 suits, buy them. If going into debt to buy a $3,000 suit to massage your ego is something you want to do, go ahead, as dumb as it is, go for it, just dont go running to Tomchei Shabbos to help with challos (this is NOT to say that every tzedaka should start questioning how much money people spend on food and clothing, I’m only talking about the person buying the clothing/jewlery and their attitude towards it).
A $5 shirt or a $555 shirt worn just to snub your nose at the next person is just plain horrible middos.
You cant legislate seichel or middos. If people want to act stupidly, you cant help it. If people have horrible middos you cant do much except offer to learn Mesilas Yesharim with them.