bloodyhell imnotmamag, you are having a bad day Im sure your cat will be fine. Firstly, you need to make sure that the cat has a blood supply to her tail, ie, nothing has been crushed or trapped, so it should not feel cold to the touch. That being the case she will need to see a vet as soon as possible, well the morning will be ok. Dont panic and go for out of hours service, will cost a mint.
If IF, you need to take that cat, explain your situation BEFORE you see the vet and im pretty sure, so long as you offer to pay in installments and pay SOMETHING straight away they will be understanding.
I know what it is like to struggle with money and its pretty horrible.
If you are really REALLY stuck with money and you can't afford to pay just now, you could approach your local cats protection league and they might be able to help.
The PDSA is awkward as you have to be in receipt of benefits and registered in advance.
Honestly im sure that kitty will be fine. I think you would notice if she had broken it as she might hold it at an awkward angle. Not always though.