My tooth hurts really bad?!

well check if theres a hole in the area. If there is, it isnt going it stop hurting until you go to the dentist and get it drilled. But usually thats only if it hurts a lot. If its hurting slightly and it gets really cold and hurts more when you drink, you have sensitive teeth and need to use toothpaste for sensitive teeth, like sensodyne(:

You need to go get that checked out. Are there any free/based on income clinics in your area? Or a dental school that would got less than a private practice office? The long that you wait to have the worse the tooth could get and end up causing you a infection. And possibly alot more money for something like a root canal.