I used to buy my cat lots of toys. I figured I was doing OK financially and that I might as well "spoil" my cat a little by buying him toys whenever I had the chance. Part of it was guilt because I knew I didn't play with my cat nearly as much as I should.
However, I soon learned that buying cat toys was a waste of money. My cat found ways to entertain himself with whatever was lying around. I think I first came to this realization when I tried to celebrate Christmas with my cat by buying him some gifts. He ended up playing more with the wrapping paper and ribbon than he did with anything I bought him.
To prove my point, I took this video of my cat. Here he is with a plastic bag I happened to leave on the floor.
He rarely if ever enjoys playing with the toys I buy him from the store. He's learned to entertain himself with bags, string, cords, leaves I drag in from outside, etc. The last toy I bought him, a self moving electronic gizmo with some sort of feather attached to the end of it, entertained him for about 5 minutes, and then was forgotten. Cost $20. This bag cost me nothing, and brought him the same amount of amusement.