boys dog has cancer needs surgery

My 14yr old step son has a dog who we just found out has cancer in his paw. Right now the vet wants to do a biopsy which will alone cost $200 or a possible amputation which will cost $900. Right now we are scraping cash together just to keep the dog out of pain but our goal is to give this boy his best friend back so they don't have to say good bye before its too soon. Dakota is only 6 years old and deserves a chance at life a life where he is desperately needed and loved. Please give as you see fit all donations are greatly appreciated and Dakota thanks you in advanced.
God Bless.