Go to a feedstore and get a bag of diatomaceous earth. Call first and find out if it's sold in small sizes. It cost me $2 for a 1 pound bag.
It can be mixed in the animal's food or applied to its coat. It works and it's cheap:
In case a bug decides to take up residence in their fur. You can protect them and yourself with Fossil Shell Flour (diatomaceous earth). When lightly rubbed into their coats it is very effective against fleas, ticks, lice, and other pests on pet dogs, cats, and their premises. You can puff it into the soft furniture in your house, the rug and all over the basement too.
Diatomaceous Earth Kills Pests Naturally - It is a mineral dust mined from quarries that kills the insects when they come in contact with it and it does vaporize or go away over time. Once it's in place it works every time and it's nontoxic..
It can also be used as an organic wormer and will kill any worms or parasites the pets may have.
* Cows/Horses get 1-2 oz per day
* Sheep/Goats/Hogs get 1/2 oz per day
* Cats get 1/2 teaspoon per day
* Large Cats - 1 teaspoon
* Kittens - 1/4 teaspoon
* Dog 100 lbs + - 2 tablespoon
* 50 - 100lbs - 1 tablespoon
* Under 50 lbs - 1 teaspoons
* Mini dogs - 1/2 teaspoon ..." -