Why buy flints for your Zippos , here's a trick that can save you from buying flints and easily get them cheap or even free.
-Empty Bic Lighter
It's not to uncommon to see empty bic lighters on the ground all over the place. Snag em, for one thing you are pickin up litter so good on you and you are savin money on flints, all round good deal.
Step 1: Startin
Start by removing the top section of the bic then pull off the flint wheel, be careful the flint stick is spring loaded and she will fly out if you aren't careful.
Then you will have to chop the flint in half with a small saw blade so that It is no longer too long to install.
Step 2: Finishin
Pop the insert out of your Zippo and pull out the flint screw/follower setup and insert your free flint and she's done, fill er up and light.
BTW I don't smoke, just like Zippos
Good luck, hope she helped!