Trent at The Simple Dollar mainly watches TV series which come in boxed sets. For them it is relatively cheap and more convenient for them to buy and resell used boxed sets of TV series. I thought it was a great idea. I decided to see if it might work for myself.
As an example I researched the cost of the movie The Pursuit of Happyness on a few online sites. The DVD runs about $2 + $3 s/h if you buy it used on Amazon marketplace. On eBay the cheapest I found it was $3.5 for cost + s/h. Half.com has it for about $4 including s/h. So you're generally looking at a price around $3-5 for a used DVD if you buy them online. The

SwapADVD is another alternative. Through that program you can swap your used DVDs with other members and basically only pay postage one direction for about $2. Net cost is $2 per DVD.

Trent at The Simple Dollar has a unique approach to watching DVDs that works well for their needs. But I still think that in general for most people a combination of Redbox and/or a 1-2 disc Netflix plan would be the most cost effective means of renting DVDs.