What is the best best flea killer out there please tell you?

Well here is a perfect list of flea and tick treatments that really work and are worth knowing. Skip this and read further answer if you want to know in brief: buyfleatickmedicine.com/dogs-flea-tick-comparison-chart/

Your best bet is going with a better name brand such as Frontline or Advantage instead of the low budget products. BUT the biggest problem with fleas is removing them from the environment. Any product will kill the flea when they jump on your animal and bite but these products are not repellants. My biggest piece of advice is treating your yard and the home if necessary. Bayer (which is the company that makes Advantage) has a product that you can buy at Home Depot called Bayer Advantage and you can get it in a granule or a spray that you can use to treat your yard. Very inexpensive and lasts 3 months. Takes care of the fleas, ticks and some other bugs. In the home, you want to vacuum, vacuum, vacuum. Fleas will not survive the suction of the vacuum. That includes not only your carpet, but any rugs and furniture as well. Make sure to get underneath furniture too. Borax powder is the best on removing the fleas out of the home. You put down the powder on your carpet, rugs, furniture and brush it down in there. You'll need to leave it down for about three days and then vacuum. It is completely safe for you and your animals. At one vet clinic I worked at, there was a product being sold there and the main ingredient was the borax powder. That product was guaranteed one year. I know someone who used the borax powder and it was 3 years before they saw a flea on their animal.

And with all that being said, when you work so hard to remove the fleas from your home, yard, etc.. remember that when you take them for a walk and you let them go in to other peoples yards. You don't know if there are any fleas there. Also, if someone has a bad flea problem in their house, they can bring them in to your home on their socks!