Amazon may change its policy at any time and there are likely ethical considerations for you before proceeding, but for the moment it would appear that Amazon Prime members can have their cake and eat it, too. That is, getting free two-day shipping and the $1 Instant Video Credit that Amazon tempts you with to choose a slower shipping method. The hack is rather ingenious in its simplicity, but first a little back story.
Our story begins in late June, when Amazon started. Instead of choosing the free two-day shipping option, Prime members could instead select the new No-Rush Shipping option that promised delivery in five to seven business days, along with a $1 Instant Video Credit to spend to rent or buy a video that's not offered for free to Prime members.
Fast-forward to this week when a Reddit user posted about a No Rush Shipping Hack (note: the post contains NSFW language) that promised a $1 video credit for all but one of the items in your cart and free two-day shipping. Here's what he did: he ordered each of the items separately, choosing no-rush shipping for all but the last one. Then for the last one, he chose free two-day shipping and found that Amazon grouped all of the items together with the two-day shipping item.
I have yet to put this hack to the test and am merely reporting on what the Reddit user posted. Lifehacker picked up the story and a comment on its post about it offers two helpful conditions that may have to be met for this hack to work. First, all of the items probably need to be in stock at the same Amazon facility. You can check by putting all of your items in your cart and seeing if Amazon groups them together to arrive on the same day. Secondly, he assumes that the hack is less likely to work on large items that require their own box.