Combine powdered drink mix, soda, tequila, and lime juice in a glass or shaker. Stir to dissolve the drink mix.
Pour into a margarita glass with lots of crushed ice. Finish it off with a slice of lime on the rim of the glass, if using. Time to enjoy!
PER SERVING (entire recipe): 115 calories, 0g fat, 55mg sodium, 2g carbs, 0g fiber, less than 0.5g sugars, 0g protein