Hello, my name is***** and I have over 20 years of experience as a veterinarian.
I am really sorry to hear about your girl's loose upper canine tooth and while I understand the temptation to try and pull it, I don't advise it. It may fall out on its own, but that likely won't solve the primary problem either.
Even though it seems loose there probably are pieces of the root that cracked and if you try and pull it one or more pieces will remain leading to an abscess. That will be very difficult to treat. Sometimes we even see small pieces of the root end up in the nose.
Because this is a canine tooth the root of this tooth is extremely long and ends up very near the nasal cavity for a fair amount of distance along the top of the root. When that tooth becomes damaged enough to loosen, the amount of healthy tissue between the nasal cavity and the root socket gets compromised due to inflammation and infection. If the tooth is removed we may end up with an oronasal fistula, or an opening between the nose and mouth. This allows bacteria and food debris from the mouth to enter the nose and we can see horrible infections and bone loss secondary to that.
If you cannot afford an extraction now you might be able to treat her symptomatically for a bit with antibiotics for the likely secondary infection while you save money for an extraction.
Your veterinarian can take dental radiographs, making sure the entire tooth and all of its root, is removed, and that the socket is thoroughly debrided and cleaned out, then stitched closed. This will minimize the chances of a bone/jaw infection and/or an oronasal fistula forming.
Either way she will definitely need antibiotics with the way her tooth is and the inflamed area around the base of the tooth. I advise letting your veterinarian take a look. It may not be as loose as it seems or there may be more than a loose tooth going on. Rarely a tooth loosens because a tumor, either in the mouth or nasal cavity, weakens the bone around the tooth and allows it to become infected and damaged and subsequently loosen.
Best of luck with your girl, let me know if you have any further questions.