Use dog sized Advantage then just use the formula for cats. It's online or I'll
mail it to you. If that's too expensive, you can use a type of spray or powder.
Get a foot long piece pvc pipe that is big enough that a cat can crawl through
it. Coat the inside with the spray and powder. Make it so they have to go
through the tube to get to their food. This way they get coated. Spray/powder
that tube once a month. You need to make sure that's the only way they can get
the food. I do this with wild skunks, opossums and squirrels. Otherwise you'll
need to get a hav-a-hart trap, trap them, spray them, give them a treat then
let them out once a month. They get trap savvy pretty quickly. You can also
sometimes just sprinkle flea powder around the food area and hope they step in
it then track it back to where they are sleeping. If you know where they sleep,
put spray and powder in there. Be careful when they start to have babies.

-> My boyfriend (he is taking care of 4 ferals) & I went to a pet store the
-> other day & i bought a expensive spray flea med  13.00 for the ferals
-> who he cant put advantage on.  He buys the food & i said i would buy the
-> flea med . i hate thinking that those little guys have to itch
-> unnnecesarity .  
-> He can put adavantage on one of the ferals but gees this is going to
-> break me. I do have a dog that i pay for his needs.
-> Recommendations for best & cost effective spray & best place to get
-> advantage
-> thanks anne

You can get it on e-bay, believe it or not. I think it's probably
cheapest there, unless they want a small fortune for shipping.

For my colony of ferals, I put Program ( lufenuron} in their food
once a month. I buy the large dog-size tablets, grind them up and
add to a couple of tablespoons of yummy wet food for each one. Follow
with a full meal once that is consumed. Half of a 400mg tablet is
enough for an average cat although overdosing is not a problem. The
dosage is doubled when treating ringworm.

Advantage can be bought in the large dog size too ( 4 ml), pulled out
of the tube with a syringe, and split between all your animals.
(remove the needle). The amount for an average cat ( over 10 lbs) is
.8 ml.

BarB