You can place your account on a seasonal hold which costs $10/month instead of your regular plan price. But, keep in mind that you won't be able to switch back to your old plan if it's no longer offered (i.e. a past promo plan). Upon return, you can choose only from the current plan offerings.
I was told that I could cancel my phone for 3 months and the activate it fr 1 month and then cancel for 2 months and then reactivate.This could be done with no penalty to the 500 minutes that I purchased when I bought the phone..