A smart way to save tons of money is to split flea medication. Frontline has the same amount of active ingredient in all their packages and only uses a higher volume for bigger dogs. To save money buy the heavier dog doses of frontline plus 89-122lbs version and each tube will last 6 months for a dog that is 0-22 lbs. For my shitzu 17lbs - I use .67 ml. for her, measure it by using a syringe. To buy syringes, go to your local medical center. 

Google Flea Splitting and it will come up with multiple hits to verify. As always consult with a vet before administering and do your research because not putting the correct dose will hurt your doggie if you are not careful. 

Overall a 3 month supply should now last 18 months as each tube last 6 months.