I recently purchased a rear derailleur alignment tool, a rather expensive purchase. After researching all sorts of different tools, I decided on purchasing an expensive model because:

1. It was the model I wanted

2. If I buy it for life, I can keep it, keep my bicycles working, and help out others with it, spreading the goodness

Sometimes, making a large purchase can benefit more than you in the long term, giving back to not only you, but the people you care about.