You definitely oral antibiotics. You shouldn't prolong it because the infection could reach you kidneys which is detrimental to your health. Right now it's probably just in your bladder, but you need antibiotics. If you took the antibiotics the UTI would go away within days. I think it would be worth the money since you don't have health insurance. Just make sure you get your money's worth and ask lots of questions at your appointment and don't worry about being annoying. Your health is the most important. The money is worth it.
You need to go get antibiotics ASAP. IT Is can turn into bad kidney infections or sepsis. They aren't anything to mess with.