This is probably the most bizarre tip, told to me by a friend, but it actually is a good idea.
For college students, or even older adults, if you are in credit debt and don't have the will power to leave your card behind or cut it up, freeze it..literally.
What you do is take the credit card that is causing you the most financial problems, put it in a cup, put water in the cup, stick in your freezer, and let it freeze.

The genius behind this radical idea is that if you're going out to make an impulse purchase, you have to wait for your credit card to unfreeze, which gives you time to slow down and ask yourself if this purchase is really worth it.

Hope this helps!
P.S. heating the water to make it melt faster, such as sticking the cup in the microwave will only ruin the magnetic strip of the card.