I assume this is the sort of thing you are talking about?
I have heard of people using baking soda to clean chemical residues off fruit and vegetables. It would be much cheaper than commercial brands but more hassle than an easy spray. I guess the idea is just to sprinkle some on, rub it around and rinse. I think vinegar or lemon juice and water would work well too.
And at least with both of those you know exactly what you are using. One product description says "Veggie Wash® is 100% natural, using ingredients from citrus, corn and coconut to remove harmful substances." Is that really all? Are you sure there's nothing nasty in it?! And if it that natural, can you make your own just as easily?
This website has some good home-made alternatives. And another one.
But virtually all the reviews I saw online seem very positive, so why not give it a go? I'd be interested to know your thoughts...