I think some people have tried placing it somewhere else. However, the upper arm is the only place it is approved for. Anywhere else may affect the readings.
I think Freestyle are trying very hard to push their Libre so have been very eager to give out trials. I would strongly recommend investigating this. It will give you practical experience of having one on your arm as well as how comfortable you are with the results it provides. Many people love it and feel it adds amazing value. However, I tried it for nearly 3 weeks (my first sensor fell off after a few days) and did not think it was worth the money as it fell off, gave hugely different values from finger pricks (which it cannot replace) and was very uncomfortable.