Grow your own basil in the backyard, on your porch or patio or on an inside window sill. Basil will repel mosquitoes when you're near it, and it's a great cooking herb.
Buy basil in the produce section of your grocery store if you don't want to grow it yourself. Purchase some each time you want to make a fresh batch of repellent.
Pack a bunch of basil leaves into a four oz. cup of water. Let them steep for awhile.
Strain the liquid and add four oz. of vodka. Put it into a squirt bottle for use.
Purchase basil in an essential oil from a health food store if you don't want to use fresh basil. Add 2 1/2 tsp. to one cup of 190 proof grain alcohol, which can be purchased in liquor stores. Transfer to a small spray bottle and shake before using.