My dog had heart worm for a while and we want to treat it but we need to know how much it costs,

I just took in a homeless puppy and he needs wormed and vaccinated but my budjet is tight.It never seemed to cost this much to have a dog. It used to be , you took them to the vet and they womed them and, vaccinated them in one day. now they want to do alot more, and they want you to come back for more visits. These things I never needed to do before and all my dogs lived long healthy , happy lives.