
Dear Guest,
some of the others have posted excellent ideas.
I too was mad for animals at your age, and my parents thought it a phase I would grow out of. I wasn't allowed a dog. If your parents are not keen on owning a dog themselves then it is probably best to wait until you have a home of your own, which I know sounds a lifetime away, and it is.
The thing is in not very many years you may leave home, to work or to go to University, and not be in a position to look after your Teddy anymore, and he would have to stay with the folks! :D If they aren't as keen as you are then it wouldn't be nice for either of them, and Fox terriers are usually long lived!
If it truly is only the cost, and your parents would like a dog as much as you then you could ask them to coatact the Wire Fox Terrier Breed clubs for details of Rescues, or breeders who may have had a dog back, that might be suitable for your family.
You may be lucky and find a WFT breeder near you who would be happy for you to come and help them with the dogs, or as the others have said help at rescue or boarding kennels!