Most of the equipment required for agility is pretty simple. You can go buy your own 1/2" or 3/4" white plastic water pipe, together with some elbows, tees, and caps, and make your own jumps, weave poles, and pause boxes. A little coloured duct tape provides decorative stripes.
Several vendors make great gear the same way. We bought weave poles, bar jumps, broad jumps, and a pause box from Murphy's Agility Equipment. We got to pick blue and red stripes for them. They're really nice and we've set them up in the living room for daily practice with Harry. It's funny when people come over, because it looks to them like we're holding a miniature track and field meet inside the house! The broad jumps are a little tall for Harry and we'll probably have to find a larger friend to give them to. For now, we're using them as guides to train Harry to back up. The bars on the bar jumps are very light and easy to knock off, so there's no danger Harry will trip and fall.
We attend many dog shows and Pet Expos to visit the vendor booths. We bought a tunnel, which also has a chute attachment, and a tire jump at these shows. These were AKC-branded. PetSmart used to sell them in the U.S., but we've never found them in stores here. They're are excellent for small dogs like Harry. I'm not sure they'd work very well for large dogs, as they are quite light. The only deficiency is that the tire is not the breakaway kind, so we compensate by keeping it very low to minimize the trip hazard. The challenge of the tire is really going through it more than anything else, so this is still a valuable training aid.
We did find a ramp for dogs to use to climb into the car at one of our local pet supply stores. We propped it up against the couch and used it to teach Harry how to walk up the dog walk and A-frame, two things it is hard to have at home. He can jump on the couch, so there was no danger of him falling too far. It helped him get used to a different surface texture under his paws, too.