Save The Kitten

We rescued a stray with a broken leg, we were going to wait until some money came in later this week to take her to the vet because she didn't seem too bothered by it. She has now decided to start chewing the paw off, there is a big open wound and we need 550 for the vet bill to get the leg amputated. She is a complete sweetheart and purs up a storm for everyone who gives her attention. She is a happy kitten and shows little to no signs of distress. We have tried going to multiple vets and shelters and they are only going to put her down without payment. She needs help asap. Please anything will help.