I'd never heard of this so I thought I'd so a search on this product. I assume this is what a Foam Gun is -
Foamaster foam car wash gun.
At first I thought it would be similar to that of a coin operated self-wash, but as I read on I realized you go over the car with a wash sponge or sheepskin cloth afterwards.
I can see the value in it especially because it seems you can use your favourite car wash soap although they recommend a special foaming soap. Thankfully it's not like the Mr. Clean system where you have to use their crappy soap that leaves a residue. I'd be inclined to use my own soap if I were to buy this.
I notice you're from Canada. Where did you pick this up?
Bernie