A flea bomb is the last resort. First try this:
A fine flea comb works very well. Then, kill them by your fingers (nails). Or, put them in the cold water - make sure that the fleas are in the water not on the surface. They die in the water for one minute.
Unfortunately, you have to vacuum all rooms everyday for one week (especially rugs and couch). You still have to use the flea comb. Do you let your cats outside?
I wouldn't want to take a cat to a vet. It is too expensive. Garlic powder work for some cats. You could buy one at a food store. Garlic does not kill them, and it makes them to get off the cat's fur.
I recommend you to buy a flea sprayer. The cat hates it, and I had a hard time because I wanted to get over with it. The sprayer contains chemicals which isn't good, but it is better than nothing. The sprayer worked pretty good. Do your best judge to read every different brand of spray bottle for the information and label - to see which one is better for you. It is not easy to pick one. I had dry organic sea powder from the bottom ocean, and it kills the fleas slowly and it works. I don't remember the name of the company.
Actually, I went to two different stores and discovered that the store has a better one and other store does not have that one.
If it is not successful, then use the flea bomb. It is a lot of work for you to clean up your apartment - washing your clothes and blankets, clean the walls, etc. I set the bomb one time, and never do it again because the chemical was everywhere in my house which wasn't healthy to me.
LuciaDisturbed - I tried to use these Frontline or Advantage, and they do not work. I don't know why.