I've found with my hairballs that if I spend a lot of money on a toy,
it's not worth playing with.  But if it's FREE and simple?..they love
it.  The best toys in this house are rubber bands (that I take away
when I'm out of sight), Qtips (that I take away when I'm out of
sight), small balls of paper, and my last kitty particularly loved
shreds from the paper shredder.  She'd bat them around like there was
no tomorrow.  Popular with all the cats is "bed mice"..that being
chasing a hand or foot around that's under the covers acting like a
scratching mouse.

But the most favorite toy of all is a broken one: a stuffed mouse with
a microchip in it to make it "chirp".  It's on a long elastic string
and you're supposed to hang it on a door.  They HATED it...until it
started chirping non-stop one night and I had to beat on it with a
shoe to make the thing shuttup.  NOW that it's silent, it's a winner.
One of my girls rips it down and carries it all over the house, making
her "gift" meow loudly, elastic string trailing 4 feet behind her.  If
we hang it up now, we loop one end around a fan blade (fan off).  She
leaps and jump and jumps and the fan turns on it's own from her
tugging at the mouse.

Expensive toys are overrated. :)

Heather