Adrian - did your Home Depot have one in stock when you went to get one?
I've not been very impressed with my local Home Depot's grilling section. They do stock a lot of weber accessories, which I love, but they are not too knowledgeable about anything. (They have had a Weber One Touch Gold floor display model incorrectly labeled as a One Touch Silver with an $85 price tag for about six months now - I am half tempted to just say "Ok, I'll take this One Touch Silver, but I want the floor model." except they would charge me for the 'assembly' they did to it)
I was looking there for a certain accessory a while ago, and I couldn't see it anywhere on the shelves so I started looking up high. I have internet on my phone, so I started running the weber part numbers on the side of the boxes I could see and figuring out what they had stored up top. I noticed they had a poultry roaster up there, so I later went back and had to get someone to go up there and get it for me. When I went to go check out, it was only $15 - which blew me away. They had a product on clearance that they were hiding on the top shelf.
I guess I shouldn't be too hard on them - they sell grills, but it's not exactly their core competency.
In any case, if you can't find one at your local one, look high. If you can't see one, have someone go check up on the very top of their grilling area store shelves. Maybe your Home Depot is run by the same monkey as mine.