Cat Scratch Fever

Instead of buying those bulky, floor-stealing carpet cat scratchers, I can whole-heartedly recommend buying one of these cardboard scratchers. We bought ours in a pack of 3 at IKEA, but I'e seen them at stores like Target, PetSmart and Walmart, too.
Besides being inexpensive, they take up less room. And when they get all gnarly from being scratched, are easily replaced or recycled.
Our cats love these things, and our carpet and furniture remains safe from claws. They can also be mounted on a wall, too.

Oreo even enjoys taking naps on them.
Here's a good top view of our IKEA cardboard cat scratcher.