You should be able to get cork floor tiles from any Home renovation supplier. In the UK it is B&Q, here in Hamburg we have Max Bauer, Bauhaus and Pratiker so you should be able to find some thing where you are. Look in the Flooring Section or try looking for Depron (damp-proofing foam), I found some 3mm thick in the Wallpaper Section at under 2 Euros a sheet. It is excellent, cuts cleanly, can be set to curved shapes and bonds together using PVA/white glue. Rigid as well when used for walls.