Cheap flea treatment for cats — multipack options

Before anything else, there's one safety point worth flagging whenever someone is choosing flea treatment for a cat: permethrin and certain other insecticides that are perfectly safe for dogs are genuinely toxic to cats — in some cases fatally so — meaning you must never use a dog flea product on a cat or even let a freshly treated dog come into close contact with one. With that said, buying in multipacks is a sensible way to bring the cost per treatment down, and there are good options available. To point you to the right one: how old is your cat and roughly how much do they weigh, is this about treating an active infestation or keeping fleas away going forward, and have you treated the home environment at all yet?

That's a good position to be in — you've already done the hard part by treating the home, which is where the majority of fleas actually live. At 4.5kg your cat falls into the standard adult weight range, so she doesn't need a specialist large-cat formulation. For a budget-conscious three-month supply I'd recommend Advantage 80 spot-on for cats over 4kg, bought as a four-pipette pack. It's an imidacloprid-only formula — no permethrin, completely safe for cats — and it kills adult fleas within 24 hours as well as breaking the larval cycle. The four-pack gives you roughly four months of cover and works out noticeably cheaper per pipette than buying single treatments. It's widely available on Amazon UK and is one of the most straightforward products to apply on a longhaired cat.

Advantage 80 is flea-only — it doesn't cover ticks. For most indoor or predominantly indoor cats that's absolutely fine. If your cat goes outside regularly and you're in an area with deer or high grass, ticks are worth thinking about, but you'd need a different product such as Broadline or a vet-prescribed option like Bravecto to get both. For a 7-year-old cat whose main issue right now is a flea infestation, Advantage 80 is the cleaner, cheaper choice and does exactly what you need. You can always reassess tick cover separately if it becomes relevant.

You can apply it to her right away — there's no need to wait after treating the house. In fact, treating her at the same time as the home is the ideal approach. Just part the fur at the back of the neck, apply the pipette directly to the skin, and avoid bathing her or letting her get wet for 48 hours afterwards so it has time to spread across the skin properly. Given you're dealing with an active infestation, you may still see a few fleas for a week or two as eggs in the environment continue to hatch — that's normal and doesn't mean the treatment isn't working. Stay consistent with monthly applications and it should be fully under control within six to eight weeks.