It's free. http://en.smath.info/forum/
SMath Studio is a math program with "paper"-like interface. It has an ability to work with systems, matrices, vectors, complex numbers, infinities and fractions. SMath Studio supports 18-th interface languages, has versions for Windows, Windows Mobile (PPC, communicators and Smartphones) and Linux. Mathcad's Like user interface.
Pros: Very intuitive, very similar to mathcad and much better for calculation than excell altogether a very nice experience
Cons: it would be nice to have an alignment function so everything could be lined up for printing off
Summary: There is nothing to dislike ... altogether a very nice piece of work, as above i would like to be able to align comment boxes but i dare say someone will do that in the near future!