I am looking to purchase my first projector ever and use it for outdoor viewing. My initial thoughts are setting up the projector inside the garage and rear projecting it onto a screen that is sitting right in the garage door opening. The garage door opening is the standard 9'x7'. I would like the best/cheapest projector with an HDMI input, that will project at least 720p. I am also not sure what the best screen size would be for that application. People will be sitting in the driveway anywhere from 10-25 feet from the screen. Also keep in mind that I could possibly move this projector to a future screened in porch to mount and shoot onto a retractable screen. Thanks!