SSI stands for Social Security Supplemental Program. That program has grown substantially over the years as it first started out as a program that supported the income of a single parent whose significant other passed away, it helped make up the loss of income to the surviving parent. It also was commonly used for those with severe mental or physical disorders who would be incapable of working when they became adults and parents could apply for it for them as children also to offset the additional cost of taking care of them. It sort of morphed into a program that adults who for whatever reason can't maintain study employment but they have to prove from a doctor or psychologist that the reason is they have some sort of mental or physical disability. These people, unlike those who get Social Security Retirement or Social Security Disability never earned what they call a work benefit in their lives or not enough of one. SSR & SSD pays out according to the wages earned over a person's life time or until they became disabled. SSI pays either a flat rate of something like, last I heard, seven hundred some dollars a month. They all get the same amount. Now if a person collecting SSI did have somewhat of a work history (I hope this doesn't confuse you) but however they calculate the amount individuals get doesn't equal that seven hundred some dollars then they get two different amounts, one paid out of SSD and one paid out of SSI. So say a person's amount totaled like five hundred dollars from the SSD scale, then SSI kicks in the rest to make it seven hundred some dollars a month. These people aren't required to pay taxes as there is no taxes to pay and they don't qualify for tax breaks like rental or utility deductions on that government program. SSI people can work but most don't because they can only earn less than a couple hundred dollars a month and after that their SSI starts getting reduced down by the amount they earn. Two hundred a month may be on the high end, I remember my brother checking into it when he was alive but it wasn't worth it, it may have been a lower amount he could earn. So if he earned, if it was two hundred a month, he'd be allowed to make that two hundred and still keep his SSI, any amount above that would get deducted from his SSI.