i want to share this with you....for some reason, i am suddenly having an absolutely horrible time with fleas....i have not had that issue before, i have always managed to keep my home/yard/dogs flea free.....since the last bout of flooding we had, i am having a terrible time with mice and fleas running all over the property....so i brought out the big guns to combat the mice and have that eradicated, safely, from the property.  Now, i am attacking the fleas.  I use demonmax for insect control all around my home, and go up 3 feet up my brick walls. Keep dogs off until the spray dries, then it is safe....with 100+ degree days here, dogs are being strictly limited to 30 minutes outside...everyone is down for naps by 2pm and i spray the entire outside home area, as well as lawn and patio areas following the directions on the container. When it dries, it is safe for animals to walk where it was sprayed....i spray it at 2pm and dogs do not go outside until the next day at 9am, just to be absolutely safe....i use this stuff every 4 months.....excellent results!  I use granules in a spreader for grass areas in my yard....again, water the application in, safe for pets easily by the next day.  
 
I will give you what i use for flea control as well as heartworm treatment on my dogs. This is cost effective for kennels, breeders, etc where we have a number of dogs to treat.....it would easily cost even a small breeder well over 2 grand a year, to treat effective for heartworms, as well as fleas.  This  is  suggestion  only....i  have used this for years for heartworms, it is effective, it has never made my dogs sick, and no one has ever gotten heart worms.  I slacked up on flea control....my  bad!!.....because the flea control used below has safely kept my yorkies free of fleas for many years.... 
For flea treatment:
The best way to deal with fleas on dogs the least expensive way
                “advice from j r enterprises” 
the best product to use for flea control is frontline plus or the new generic version, petarmor. Many people do not use frontline plus because of the high cost. If you have a 20 pound dog and buy a 3-pack of frontline plus from the average store you will pay about $45 which is $15 per month. 
To lower this bill considerably, do the following: Google online for the cheapest places for petarmor. Buy the 3 pack of petarmor (same as frontline plus) for the largest dog. A 3 pack of petarmor for 89 to 132  pound dogs is only about $13.
If you have a 20 pound dog you can split each tube into quarters and give one dog 1/4 of a tube. This will let you get 12 treatments out of this 3 pack and this averages out to a little over $1.00 per month.
It is easy to draw 1/4 out of a tube with a little 20 cent 1 cc syringe. Remember, for economical heartworm prevention, go to 
www.heartwormprevention.com 
( the calculations/"majic number" is .0305cc/lb for our small dogs): 
 Calculation......    .0305cc/lb x weight of dog = dose of topical application.
Example.... 6# dog = .18cc,   7# dog = .21cc,  etc.
Much savings!!!  
Look up this same site, jr enterprises for topical heartworm dosing....
This will save you hundreds of dollars a year on dosing your yorkies topically for fleas and ticks....
He has heartworm med that will save you hundreds of dollars as well....no off market drug, something used for many, many years.....