Does it cost anything to call a vet?

Just in case if (when I get them) my guinea pigs get sick or hurt, I will want to call a vet. But, I want to make sure you don't have to pay them somehow to do that? I don't want to hear anything about phone bills and stuff, besides that. Do I have to pay the vets (somehow) to call them and ask a question, or ask for advice about my guinea pigs. And if you don't know, don't just give me an answer your not entirely sure of. Thanks in advance!