Which vaccines are essential for dogs and when I should inject them?

the 7 in 1 shot (available at Tractor Supply) is very important and is cheap. You should give it 3 times to a puppy (timing cycle on package) and once a year to an adult and can be done at home without issue. The other important vaccine is a rabies shot and you can usually accomplish this easily at SPCA clinics and most cities have cheap ($5.00 rabies) clinics every now and then where you can get both of these shots without the hassle and cost of going to a vet. But you will not get heartworm medication at these clinics and this is essential and must be gotten at a vet. You can give you dog the heartworm medicine for a horse but if you give the wrong dosage you will kill you dog (not recommended) and your vet will run titers on your dog to see his condition in relation to heartworms.