There is a free trial version of the materials in the National Library of virtual manipulatives. Math topics Numbers and Operations, Algebra, Geometry, Measurement and Data Analysis & Probablity are covered. I did not come across anything asking for money so I a not certain there is a cost. There are tons of manipulatives to access from each of the above categories. This site is associated with the Uta State University.
"Readable is an application that helps you read more of the web. It transforms text on any website using fonts, colors, and layouts of your choosing.
By presenting content in a format that you're comfortable with, Readable makes the reading experience much more enjoyable - and faster too.
Readable is the most customizable solution for manipulating content (on the web) and making it readable. It's also very simple to use and completely free."
Thinking Blocks is a suite of learning tools designed to help students solve math word problems accurately and efficiently. Using brightly colored blocks, students model mathematical relationships and identify known and unknown quantities. The model provides students with a powerful image that organizes information and simplifies the problem solving process. By modeling increasingly complex word problems, students develop strong reasoning skills which will facilitate the transition from arithmetic to algebra.