[jfzoid]

Fancy business terms that'll help you spend money consciously:

1. Return on ROI: will I use this enough to get my money back

2. BATNA: is there something I can use that is an alternative (yes, I know not exact definition)

3. Opportunity Cost: what else can I buy with this. As I am writing this comment I am thinking to myself "a croissant and latte every morning, or sushi once a week"

4. Time value of money: is this saving me enough time to be worth it

[pjmorris]

"Best alternative to a negotiated agreement" (BATNA) is from 'Getting to Yes: Negotiating Agreement Without Giving In', Fisher, et al. The idea is that you want to be aware of what your options before entering a negotiation.

[LudwigNagasena]

The opportunity cost is something that should be taught to all people, it is a powerful concept that can help people think straight. Everything else in your list is actually just a particular application of it.