Some of the people who are involved in the "Buy Nothing New In April" challenge have been recognizing that they are saving quite a bit of money.
Now, some joined the challenge because they want to get out of debt. They will want to pay down those debts with the money they are saving. More power to them! I've certainly been there and done that!
Some are trying to find ways to give up part of the family income so that a parent can stay home with little ones. I've been there, too.
Some may want to make some expensive changes like solar panels on the house. Some are very invested in supporting environmental initiatives, and they have a list of organizations to which they would like to direct more funds. I'll admit I haven't done that yet, but I understand where they are coming from.
Here's another suggestion:
"If anyone has material possessions and sees his brother in need but has no pity on him, how can the love of God be in him? Dear children, let us not love with words or tongue but with actions and in truth." 1 John 3:22