muphy has a flea collar i change every 3 months and she's fine. although be careful it your is an outside cat make sure it one that will break if it gets caught on a branch or something
frontline is blinking expensive, but nothing else works like it. from bitter experience of using cheaper stuff, i had to have a man in a suit come round and spray the house. and i mean a man in a paper suit with a canister on his back, not a ben sherman suit