It's easy enough to make your own mix.
3 large stalks celery from the heart, including leaves, plus extra for serving
36 ounces tomato juice
2 teaspoons prepared white horseradish
1 teaspoon grated yellow onion
1 lemon, juiced
1/2 teaspoon Worcestershire sauce
1/2 teaspoon celery salt
1/4 teaspoon kosher salt
12 dashes hot sauce (recommended: Tabasco), or to taste
1 1/2 cups vodka
Cut the celery in large dice, including the leaves, and puree in the bowl of a food processor fitted with the steel blade. Process until finely minced. In a large pitcher, combine the rest of the ingredients except the vodka. With the food processor running, pour 1/4 of the tomato juice mixture into the food processor through the feed tube. Then pour the contents of the food processor into the pitcher with the remaining tomato juice mixture. Add the vodka and chill. Serve in tall glasses over ice with a stick of celery.
I make this frequently to keep in the fridge (minus the vodka). It's a whole lot tastier than just plain tomato juice or V8 juice.
If you have one of those hand blenders (not an electric mixer), it's even easier. You can do it all in one container. Simply chop up the celery into chunks. Add some tomato juice and then go at it with the hand mixer until it's chopped fine. You can also do it in a blender, but don't liquify the celery...just chop it until very finely chopped.