I concur with other comments that PM does offer a 30day option although the discounts are usually better on the 90 day plans.
The other advantage of 90 days is that the data is allocated in 90 day increments - so if one is a heavy user one month can be more cautious the next.
Admitedly if one decides to leave with a 90 day term - it makes it hard to time the depature to be near the end so as not to waste anything... but then again - think about how much one saved during one's time at PM.
The other aspect of pre-paid that i like is that data just stops if not part of you contract (whether u used too much & hit limit - or - u r near border & in roaming mode) so that one avoids unexpected data overage changes (which just went up for most of the big co's).
I'm on the fall special & don't see anything else that fits quite as well - although those plans from freedom get slightly tempting (high data at LTE & then step down to slower for the unlimited aspect) and like to support companies that compete but would ensure service is relaible (i.e. low frequency rollout) & more phones that work with network.
