The Pop-Up Bag from Target - $10
I took these photos near the weave poles so that you could see the size. The diameter is 19" so it would not work for all dogs. But for the toys, small dogs and some medium-sized dogs this is a great practice tunnel. You can work sends, discriminations, angles for example. It's nicely portable and stiff enough to hang a chute from to make a nice portable practice chute.