The tunnels you can get at kids stores, like Toy's R Us, for around 20$, maybe even walmart.
Jumps, well if you can a hold of some PVC, you can make pretty inexpensive ones,
See saw, if your not looking for much "height" and just doing it for fun, get a plank that is atleast 12" wide, and around 6 ft long, place it on a brick/cement block ..
If you can get a hold of THREE planks, you can make yourself a dogwalk, by using a set of really low saw horses, (I bought a pair for 25$ at a discount store),,hinge the boards together, and you've got a short dogwalk.
Weave Poles, get those stick in the ground plant stakes,,
Here's a website with pretty reasonable agility equipment for sale
www.affordableagility.com
Also check out ebay
Diane