Switching wireless providers only to find that you don't get your new carrier's signal in your living room is the pits. T-Mobile is helping residents of Boston, Massachusetts; Austin, Texas; and Atlanta, Georgia avoid that particular pickle by offering 30-day trials of its wireless service. Prospective customers in those three locales can request a portable Wi-Fi hotspot loaded up with a T-Mobile SIM that's theirs to use for up to a month or 30 gigabytes of data use.
Aside from residency restrictions, there don't seem to be many strings attached; you can use the data however you want, wherever you want. You even don't have to stay in the cities the trial is currently exclusive to — you just need an address in one of them to request a trial device.
Once you've finished the trial, you can return the hotspot to a T-Mobile store or give it to someone else who can then request a new SIM card to try the network out for themselves. You can even keep the device at no charge, according to the program's FAQ, although it won't work without an active T-Mobile SIM card in it.
It's not clear if there are plans to expand the trial program beyond the three seemingly arbitrary cities in which it's currently available.