Clarice needs water heater

Hello everyone! I am a medically retired educator. I have RA, fibro and a number of related conditions. I also have somewhat limited vision within 5 feet. I am on Social Security Disability and a very small state disabilty pension (I'd only returned to public school teaching in 2000).  The docotors have just put me on stronger, invasive meds to try and control the RA. It's attacking organs. I've hesitated to start a new account, because it's very hard for me to ask for help. Unfortunately, I'm up against a wall. My mobile home will be paid off in February and I couldn't have even found this place to live without my great friends! I love you all. Unfortunately, the water heater was water heater has to be replaced. Mobile homes require vented water heaters. the cheapest I can find is nearly $900 and I have to have it installed and the horrible job of plumbing under that part of my house done correctly.  I'm crying because I hate to ask. I've worked hard all my life and I never imagined that Id be struggling just to survive. I know that everyone has their own expenses. I DO understand. I just don't know what else to do other than ask.
I want to get stronger again and be able to have happy times with my kids again, but I have to be able to live to do that. The stress of no water is very hard on my illness. PLEASE help.