I saw a very small tomato plant (I think less than 10cm) in a tiny pot, and it was producing tomatoes. What varieties of tomato grow like this?
Seeing as you mean something like this:
You really have two options:
Either way, there should be "growing", "plant requirement", etc information that comes with your purchase, regardless which option you decide to go with...
Good luck! and please post back a photo or two if you do grow a miniature tomato plant...