You may think that dog training aids are out there for you to spend money and not actually reap any benefits from. That is not the case. Dog training aids are there to help you succeed in teaching your dog, this could be teaching him obedience, agility or any other type of teaching you want to do. There are many aids available but only a certain few will work with your dog and his temperament.
I find the best training aid to be treats, small pieces of human food chopped up and given to him when he has done something good has always worked wonders, that is unless your dog doesn't really have an interest in treats. This is a really cheap method of a training aid but if you want to blow some cash there are hundreds of options available for you.
For dog agility training aids that are available are things like anti bark collars, many dogs have a problem when they do dog agility that they bark constantly basically because o the hype involved. Anti bark collars do one of two things or sometimes both, they give a small electric charge when your dog barks and spray some water up into their face. People may think this is cruel but it is completely harmless it just lets your dog know that barking is not acceptable. These collars are available at pet shops and on the internet and are not to expensive.
For dog obedience some dog training aids that are available are dog clickers, the newest craze out on the market which allows owners instead of associating sit with a word they use a click instead and reward with treats, no punishment allowed. Another aid available is a harness; this gets fitted around your dog's upper body so when you are teaching him to heel a slight tug on the harness pulls him back completely. The harness is a widely used obedience aid and is greatly used for bigger dogs such as German shepherds and Rottweilers.
There are also dog training aids available for around the home and are simple and effective. Many people turn to dog training aids when nothing else has worked but they don't have to be the last thing you try, with aids so cheap these days there is no reason why you cant invest in something that will make your dogs learning process a lot more exciting!