We made jumps and weavers from PVC including the supports, wings, the lot. It is not "that" cheap if you get all the correct T-piece and 90deg angle fittings etc but will last for ever and is so light to move around or store. The full directions/specs we found on a South African agility website when doing an "agility equipment dogs" sort of yahoo/google search. It has all the specs, materials plans etc for Dogwalk, A-Frame and see-saw as well. We got all the materials then sidelined into Flyball so they are not built (except for the jumps/weavers). I've thrown out the URL but it is sure to be there still.
Clints Warehouse sometimes get good length dog tunnels in their pet section that my little Rotti has no problem running through. But they sell out fast. A dearer indoor solution is the cheap round laundry "baskets" nylon on plastic spring-wire frame (Clints or $2+ shops). Cut the bottom fabrics out and shoe-lace the top and bottom wires to make a tunnel: sometimes they are on "special". They collapse down for easy storage, and again a lab-size dog can do it easy.
