I found one of these Sterno stoves up at the local Walmart for $5. Surprisingly, it works quite well for small twig fire cooking, not quite as good as the little solo stove, but for $5, what would you expect. It folds up nice and flat, and only weighs 11 oz. The frame is aluminum, the grate and struts are steel wire.

You can spend more I guess, but I got this to work just fine. The Solo stove serves a slightly different purpose, but another fold up twig stove doesn't seem necessary.