Where do you buy your pet meds? I've been just buying from our vet, but Roscoe is close to adult size now, so it's time to buy several months at a time and start saving a little money. I've used 1-800-pet-meds in the past. Are they still good value and quality? Heartworm meds will be expensive no matter what, but I want to save where I can without compromising on quality and Roscoe's health.