I bought and used one of these from Walgreen's last year. It was like $7. It worked really well for me. I didn't even hang it up until August and I still got about a dozen small tomatoes. It doesn't look great up close but from a distance, it's very pretty hanging there with all the foliage. I had it hanging from a trellis on my roof deck so it got tons of sun all day. It works really well as advertised and it grew fast and prolific.
A few caveats: you really REALLY must water it every day. The way it is designed, the water flows through so it can't hold much water at one time. And the greenhouse style of the container, which keeps the soil warm and helps the plant grow faster, also makes the soil dry out very quickly.
Also due to the design, you have to use a pretty large seedling when you start. The first time I tried it, I used the size recommended in the instructions (about 4 inches if I recall) and the water running through when I watered gave it such a beating that it didn't survive. I would recommend a seedling of 8 to 12 inches. But once you get it established, if you water it daily, it will go crazy.
A few people have noted that these are fragile. It's true, at least of the plastic top which you have to be pretty ginger with. The wire lines and metal triangle hook it hangs from were very sturdy but now show signs of rust. I don't know for sure but I won't be surprised if one snaps during its second year outdoors.
I would not plan on using this indoors unless you can keep a bucket directly under it to catch the runoff, or have some large basin or flooring to catch the runoff. It really gets everywhere and it's hard to see what you can do about that. Also, I think you would need south facing windows for that to work. Not uncommon, but worth considering.
I got just one last year as a tester and was very pleased so in for six or maybe just four, haven't decided yet.