While rummaging around

[KestrelBike]

When I carried one during college days, I had to surrender about 3 of these (separate occasions) to airport security when I forget them in my wallet at the airport.

[Irving]

I dont know what 10 is but these things run around .50 cents to a dollar on every deal site on the internet.

This. Except I paid $5.00 for mine when I HAD to have one. Later they started showing up for free.

When I carried one during college days, I had to surrender about 3 of these (separate occasions) to airport security when I forget them in my wallet at the airport.

And this. I used to keep mine in my wallet until I forgot about it going to court. Now it sits on top of my beer fridge in the garage.