tabbytom-Whoa! Hold your horses everyone. In the first place, does your cat has fleas Mike89 ? If she dosen't, I think you don't have to worry that much at the moment.
If you can't find a good flea treatment where you are or it's expensive online, you can try using food grade Diatomaceous Earth.
Here are some discussions on it. I'm not asking you to use it but just an option for you to consider. Any topical treatment, we must use with care. So give it a read and see how it goes.
Using diatomaceous earth for fleas
Advice Desperately Needed!
https://thecatsite.com/threads/question-about-diatomaceous-earth.317137/
For more readings, type Diatomaceous Earth in Search option.
Isn't the point of a flea preventative to use it before a cat has fleas. Just as you mentioned Diatomaceous Earth, can others not have a discussion about topical? I don't think anyone is telling anyone else what to use. It's just general conversation.