The fastest and best way to go about this is to take your animal to an herp vet have a culture done and have the proper anti-biotics prescribed.
Most vet will do payment plans and there are also credit cards designed for medical emergencies.
With pet ownership comes great responsibilities, providing proper veterinary care is one of them and since you have 15 snakes in your care it might be something you want to give some thoughts.
This is not like a human having a cold this is a RI in a snake that requires proper care and what you are doing right now is just alleviate the symptoms.
http://ball-pythons.net/forums/showt...tory+infection
http://ball-pythons.net/forums/showt...ce-Reptile-Vet