I recently needed a projector. It was a one-off thing so I first looked at renting. Even if you can get the "from $99" rate, you're still talking more like $134 after shipping for one day of the simplest, most basic projector in existence. If you up the quality of the projector, you're quickly at $175 to $200, or more.
So I bought this Infocus Projector from Amazon for $399 (the price may only display at right under "More Buying Choices"). It is much better quality than the rental, I can use it for more than one day and I get to keep it forever. I anticipate using it at least once or twice more and that is all it takes to justify the cost!