I am disabled and have several inventions but need capatal. How do I aply for a grant

I have 3 inventions but I am disabled. I have had over 20 opperations so I am very poor.
Two inventions are to modify an all readyexsisting product. I is way out there but might be a great on if it works. Is there any way out there that I would qualify for a free grant on one of the 1st 0nes. I am dot onlyseveraly disabled and really poor $600.00 a month is all I get.