I everyone, for a tunnel I brought the kids play tunnels (depends on the size of your dog of course! but my staffords fit through quite easy) they dont bend, but they are still good to get your dog to go through as a practise. They were quite cheap as I brought them at clints crazy bargains (or somewhere like that), they fold away for easy storage. I secure them to the ground with a few tent pegs and 'hockey straps'.
Cheers
Elaina