Here is another leveled site. This site has leveled reading and math. The thing I was really excited about with this site is that it doesn't cost an arm and a leg. Many of the sites I look at charge tons and for a family like mine that would like to use it for multiple children the numbers add up quickly. This AdaptedMind only charges $9.95 a month.
I played on the site for a little while and found a claim that the site's curriculum is aligned with the states standards. With the majority of the states currently using Common Core Curriculum that is probably true.
There weren't very many bells and whistles to this site which can be good for some kids. I also didn't see any ads so kids can't easily get to places they shouldn't be. They have a reward system set up for the kids as they earn points for completing assignments and earning points.
I really like that this site does both reading and math so you only have to pay the one monthly fee for both subjects.