How do you live on disability?

For those of you that live in the US how do you live off disability? I would get 1200 a month. I have 3 kids to support as a single father and I am told I need a service dog which if you dont want to wait you have to pay. But without the dog I still can't survive on 1200 a month. So if I can't work and I definitely can't live on a 1200 a month budget what do you do to get by?