That url does provide good advice but keep in mind some people live in areas where the economy is depressed and jobs - even the ones you mention - are hard to come by. That said, one can still be innovative and she indicated she is a poetry writer. I rec'ed the poerty night for felines (which could become a tradition in your community) As an oncologist, I see many people coming up with wonderful ways to raise money for my patients who are facing long stays while they fight cancer - I live in Canada but sometimes people have to travel 8 hours plus to get to the hospital I work in and they need money for accomdations and so forth. Otherwise, their care at the hospital is already paid for by our natinal medical system.
So there are all kinds of events you can hold with feline themes even. Get your friends and family involved. If you do not have a job, there must be something you can do. (and I must say, most teens I meet in my work have a job - and thankfully their employers (whether they babysit or work in a call center) keep their jobs for them till they get well - it's the law anyway but of course people who employ babysitters do not necly have to keep the position open for them but most do.
As I noted before, your parents could help you - even if you have to pay them back, it's better than a bank loan. Grandparents? An advance on your allowance? Mowing your neighbour's lawn? Babysitting? Starting a petsitting service? A car wash? Start a Friends for Felines Foundation with your kitty as a recepient (be upfront about this) and raise money with a dinner, music night, collect pennies, make a quilt with a group of friends, the list is endless.