I do not have cats, but I have tried Biospot on my dog and it was a complete waste of money. I used one tube on her and when it didnt work, I ended up throwing the other tubes away and buying the good stuff anyway. I usually buy my flea treatment online at Drs. Foster and Smith. I have found that they are usually the cheapest place I could find.

Just a note about buying flea medicine from Ebay, please be careful as many of the items on there are much more inexpensive, but they are not approved for sale in the US. They carry the same brand name, but are not for sale in the US. I may be over cautious, but I'd rather not put something on my pet that wasn't approved for sale in the US.