This one right here is good to start with or anything similar..
BenQ MX522 3D Ready DLP Projector
- 1024 x 768, 3000 Lumens, 13000:1 Contrast Ratio
- VGA, HDMI, S-Video
this one is about $430
BenQ MH680 3D Ready DLP Projector
- 1920 x 1080, 3000 lumens, 10,000:1 Contrast Ratio
- VGA, HDMI, USB
this one is for about $800
Resolution matters but not initially unless you are doing mappings which are very very complex and small in size. Because smaller the mapping surface or more detail it requires the higher your resolution has to be so that the pixel size is small.
I have 2 projectors they are both 1024 x 768 one is 3000 lumens the other is 7000 lumens and they work great .. so you can absolutely start with the first option.