About the cheapest you can go is a Retriev-R-Trainer or similar design. The problem with all of those is that the bumper leaves from your side and if the dog is sitting with you, it doesn't learn to look out. Birds don't come from where you and your dog are standing. You can join a retriever club and get with their training group and then problem solved. If you train alone, I'd suggest a launcher from Thunder Equipment in western PA. They make a 2, 5 and 10 launcher and now even make a 1 launcher for $399. You'll also need the Dogtra or Garmin/Tri Tronics electronics. Uses MAP gas for the "bang" and the launch. http://www.thunderequipment.com/products/