[KennyP]

If you decide to put a tube in the tire, put a patch inside the tire at the leak. Might have to remove/trim the plug. I've had good luck just putting tubes in old tires, saves a few bucks. Lots of times, you can't match tread pattern of the old tires. So it's either buy two new tires, or tube the leaky one.

 

[KennyP]

Call a few local lawn mower places, they should have a tube in that size. Even some big tire stores may carry them.