Use for cooking, they feel very light I'm almost sure they are some sort of alloy but they do feel like they might have a coating to me, errr it's just not worth it I think i might condemn them for parts trays in the garage.
They look like aluminium to me too, especially since you say they are light.
Just Googled and found that, "The best cake pans are made of metal, specifically aluminum or aluminized steel. Aluminum is the best material for baking the perfect cake because it distributes heat quickly and evenly. When it is paired with steel, you get pans that are durable and resistant to warping or denting."
Since they were so cheap, my guess is aluminium. I have no idea if they would also be coated in teflon. If they feel waxy my guess is that they might be? Apparently aluminium tins can be coated.