Always have Correct Change in your wallet: make a special wallet for it

[mouser]

this is cool.

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Some people carry change purse with them where ever they go, but you won t use most of those coins. Why carry coins that you won t use? So what is the fewest number of coins you can carry that allows you to produce any exact change? And then find an inexpensive way to carry that in your wallet.
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http://www.instructables.com/ex/i/716B973651031029AC23001143E7E506/?ALLSTEPS

from boingboing

[jgpaiva]

Interesting idea!
I still prefer to just not carry money at all, and always pay with plastic money,though.

[noth(a)nk.you]

I still prefer to just not carry money at all

You sound like every woman I've ever gone out with!

Linked on the Instructables page, I found a neat game along the same topic.  The idea is that you get 10 [US] coins (3Q, 2D, 1N, 4P) and a whole dollar to pay for an amount of $.XX.  It's pretty good, actually--there're a few levels of "difficulty" coded in.  If you're not bored to tears by my description, try it here [changecard.com].

edit: A better description would be: mental gymnastics.

[noth(a)nk.you]

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