Aside from the 2 months before Christmas, it appears this is another one of the biggest bargain seasons of the year. Most carriers are offering 'Back to School' specials that are geared toward the college student using a phone away from home, but can easily apply to your own wireless usage.
We don't have a list of these individual deals, but the best way to find them is to choose your favorite carrier or prepaid service and see what their offer is like today from a site that lists offers from ALL the cellular services. Other Back to School deals can be found at the top wireless retailers, Lets Talk and Wirefly.
These deals should disappear by September 1st, then you'll need to wait for Black Friday.