Alton Brown from Good Eats recommends an unglazed terra cotta tile as a bread and pizza stone. There isn't an issue with being "food grade." Terra cotta is a clay, and if it's unglazed then it's just clay-- nothing added. The firing process assures you that there is only ceramic there (nothing else can withstand the temps- that's why the space shuttle is covered in ceramic tiles). One does need to worry about glazed ceramics being appropriate for food-- occasionally cheap glazes (usually non-u.s. made) are created with too much lead and can contaminate food. (BTW I and my partner are potters, and he has a degree in ceramics.)
I also use the unglazed floor tiles that I bought from a tile outlet and they work great. I used to use pizza stones and liked them but I broke several and they were too expensive to replace. The tiles seem to work well and the non-food grade aspect has not killed us ye..........................
I think the bread stone just adds to the easy baking system that I have set up now in my house. We got a bread stone for pizzas years ago from a local kitchen stone and it just keeps going. I vote for having a good quality stone.
Here is another vote for an upside-down cast iron pan...I am using my grandmother's 16 inch chicken fryer, upside down and with a flat bottom, with great results so far. This is a very heavy pan (today it would have been cast with two handles!) and cast is a very good heat-sink so that the bread does not cool the surface down. I will eventually be looking for a terra-cotta tile to replace it I suppose, but the pan works so well it is hardly worth the effort. The only shortcoming is that the cast iron does not draw the moisture out of the bottom as well as a more porous stone, but the bread is fabulous. I have the pan, I do not have a stone, and I want bread...
I have used an unglazed terra cotta floor tile for baking over the past year. It's only 3/8" thick however, and it broke last month, not catastrophic however as it only cost a few dollars and just cracked in half after many uses. Looking for a sturdier replacement, at the supermarket, I found a 15" X 1/2" round pizza stone for $14, with a steel handle frame. It works great, and I love being able to handle the stone easily.
There shouldn't be any health issues from using terra cotta unglazed floor tile, as others have said, because terra cotta is just fired clay, used over the eons for baking. But you really should avoid all glazed flooring tiles for baking, as there may be lead in the glaze, even if you use the unglazed side.
I don't know about the unglazed tile (not food-grade material) so I'd be reluctant to use one. We've had a round pizza stone for many many years and it works great for this bread! I don't know what bad reviews you've read, but I think you just need to make sure that the stone is thick. Now I am looking for a larger stone; there is a 14"x 16" that seems like it will be perfect for baking a couple loaves at once.
May I also suggest a terracotta pot planter base like the ones that your plant pot sits in to catch the water. We found a nice big unglazed one at a plant nursery/gardening supply that is about 16" diameter, including the lip. It is very sturdy as it is meant to hold a heavy pot full of wet earth and plants. Just made some bread with it for the first time today, washed it thoroughly before use, dried it slowly in the oven at 190F for a couple of hours to make sure there was no trapped water inside that could cause it to split or pop if it were heated too quickly. If you wanted, I guess you could bake on it upside down to avoid any issues from the lip getting in the way. I think it cost us about $23, most pizza stones that I've seen run double that price for a good stone of that size. I can say it works fine for bread, and I'm sure it will work great for pizza as well.