I've only ordered advantage for my cats online and I've been using Entirely Pets. They seem to have great prices and will e-mail me coupon codes so I can save even more. They're also in Northern CA so it only takes a day or two for me to get my order. Since I have 4 cats, I always order the largest dog advantage and then I measure it out. It lasts me a long time too and since I've been using it I've never ever had any more flea problems.