I was thinking about getting a DaLite screen, but i'm totally lost on what i need...

here's what i'm looking for:

-Fixed position (will not be moving it, never need to roll it up)
-about 100" diagonal 4:3
-cheap

it will be in my basement, lighting is always low and brightness is not a big problem (a little brighter would be nice)

I know a wholesaler that can get almost any model 25 - 50% off so i'm not worried about where to buy, i just would like to know what model to buy

Thanks for any advice!