I need a javascript pricing calculator creating to use within my website which is being created in Adobe Muse

I think this will be a fairly easy project. I am looking for a javascript calculator to include within my website. I don't really mind which language is used provided I am able to edit the material and prices and it will be suitable for inclusion in a website being created is Adobe Muse. The calculator needs to be almost identical in operation to the one included on the following website [login to view URL] I need to be able to edit the materials and the corresponding prices per m2. ALSO, a couple of the products have a maximum width, roll material so length isn't a problem. Also, a figure to cover my carriage expenses needs to be added to SOME of the products. This will be something like £8.50 for orders totalling under 5m2, £20 for orders over 5m2. Some materials will not require a carriage cost.