It it tastes good or is fun to play with, they are happy. Tie in a knot. Dangle the bate and reel in the cat. Scratching post is another easy one. Run down to the local hardware store, find a piece of wood that fits your fancy.
Posts can be anything from a two by four board to something fancy, depending on desire.
Carpet to cover it is easy to find, most carpet stores have samples they will sell for a dollar or two. If your post is larger than a sample piece will cover, ask a carpet installer to save you a scrap off one of their jobs. This may take longer, but the price is right. Once you have your post and carpet, glue carpet onto post, use a staple gun on edge. A special bed, cats much like the dogs will many times enjoy laying on their owner's clothing.