I have stoneware from Pampered Chef. I do not cook any gluten items in it as it would not clean out (glass and stainless can do double duty usually IME but only after through washing).

I would not purchase anything for baking in that seems less than quality. You do get what you pay for. Things I'm using to put food in really matter to me.

As for cast iron, I guess we lucked out b/c my cast iron pans have never been used for gluten foods. Southern Corn bread (is not flour by nature), bacon, sausage, eggs, and gravy made with corn starch... My dh bought be a set when we got married, I bought a bigger (like 16") one just before my ds2 was dx'd. I can barely pick the pan up!!!