The two most common flea species to cause a nuisance in homes are cat fleas and dog fleas, but either will feed on any mammal. Like bed bugs, not everyone will react to flea bites so they can get out of control before you notice they're inside. The photo shows just how small they are compared to a thumb nail, so you can easily imagine them going unnoticed.
The first step in flea control is removing the source of the infestation by treating the pet that is harbouring them. After that, we treat carpets, furniture, hot spots and any other areas fleas commonly lay eggs. Cost depends on the scenario and size of treatment area, but generally starts around $250. This does not include treatment for the animal, we let the vets take care of that.
Many people vacuum as a home remedy for flea control. This can work if you empty the vacuum bag or bin (do vacuums have bags anymore?) immediately in an outside garbage where they can't re-infest an animal or building. If you leave them in the vacuum, they'll just make their way out and carry on. If you collect eggs in the vacuum, they can hatch in there and resume business as usual.
If you aren't sure if your pet has fleas and don't want to invest in a flea brush, simply dampen a paper towel and dab it several times at the base of the tail. If there are fresh flea bites, you should see dots of red/brown blood. Of course this isn't an assured method but can help you decide what to do next.