Free, yes I think this one actually is. It's a web browser for youngsters! It was made by a grandfather who has a grandson on the autism spectrum. He made it for kids with autism, but really it sounds like something kids who are typically developing from would benefit too. It omits the right click on the mouse and makes the computer a little simpler.
"John LeSieur is in the software business, so he took particular interest when computers seemed mostly useless to his 6-year-old grandson, Zackary. The boy has autism, and the whirlwind of options presented by PCs so confounded him that he threw the mouse in frustration.
LeSieur tried to find online tools that could guide autistic children around the Web, but he couldn't find anything satisfactory. So he had one built, named it the Zac Browser For Autistic Children in honor of his grandson, and is making it available to anyone for free."
So how can you download it? Just go to ZacBrowser.com