Well by the looks of your username I am assuming you are not yet an adult. (please correct me if you are :wink: )
My first bit of adivse would be to talk to your parents about getting a chi. If you are still in school they are going to be the ones who will care for the chi when you are gone.
Second, I would read up on the care for a chihuahua. There is a great sticky up in Chi Chat that lists a lot of great books you should buy and read before deciding on a chi.
After you do that I would do a search of your area of chihuahua breeders. Definately do not go to a pet store. You should be able to do an internet search for breeders in your area. I do know there are some members from your area who have chi's and hopfully they will see this post and give you more advise.
I cannot stress enough to do you research before buying a chi. They are not the easiest dogs to care for and are not reccommended for first time dog owners, however, if you do your research first and really get to know what taking care of a chi all includes then you should be okay.
Lots of members come to this site even though they do not own a chi simply to get as much information as possible. I would suggest hanging around and participating in threads and asking as many questions as possible while you search for a good breeder. Again, you want a GOOD breeder who will probably interview you first before sending you home with one of their chi pups. It might seem like a lot of work but trust me it will be worth it to have a nice healthy chi pup.
Again, I am assuming a lot in this post and I am not implying you are going into this with no information at all, this is just advise that almost all of us who have a chi would give to someone who is thinking of buying one.
If you go about this the right way, you will find that chi's are probably the most awesome dog you can own, but I am a little bias :wink:
Look forward to hearing more from you!
EDIT: Also please introduce yourself in the new members section!!!