I've gotten 2 of the aluminum-looking ones on ebay. One is small but the other is the size that you really need. I used the small one at Christmas for a gift to my niece. I threw in a bid because the bid was really low, which I liked since the shipping was kind of up there, and I got it. I can't remember which seller, but you might make sure to check the dimensions of the case before you bid or buy one outright. They are both wonderful and I'm thinking the large one I got for less than $40. They lock, have movable dividers, and shoulder straps.
There's also a topic with some links to online sales of different cases that come in different colors & are pretty reasonable.
I haven't looked in the luggage section of department stores, but I've seen some like the Caboodles brand at Walmart that were smaller versions in the cosmetics aisle.