If you need to inexpensively cover a bare concrete floor and have it look halfway decent you can use paper bag pieces, white glue, and polyurethane to give a finish that looks a lot like leather.
Recycling weblog Recyclart gives the basic procedure and a few step-by-step pics of the process. You'll want to tear brown paper bags or rolls of brown paper, crumple the pieces for texture and dip the pieces of brown paper in a 50/50 mixture of white glue and water. Spread the wet paper on the floor surface and smooth out any air bubbles and then apply your first coat of polyurethane. Let that dry completely and then keep adding additional coats until you're happy with the finish. The author of the method used six coats total.
This sounds like an interesting way to finish floors of a study or workshop on a budget while keeping an attractive appearance. I encourage anyone who is sceptical to check out the photos at the source link below.
Paperbag Floors [Recyclart]