I'm having such a hard time. My vet is recommending Nexguard but for a year for both of our dogs it is about $400! There are less expensive options such as advantage and frontline plus (which we have used in the past) but she says they aren't really effective anymore. I just don't know what to do. I want something that works but goodness, $400 per year! There are too many choices. What do you use? And where do you buy it?