Sanding dust

I'm looking for a reasonably priced (less than $200) positive flow mask to help combat sanding dust. Anyone have any experience or recommendations with these type mask or other things you might recommend?

I use what is know as a 3m Airmate5.  Its a belt mounted filter system with a hose that runs to the back of a faceshielded  hard hat so to say.   This is the model before the 3m Airstream.  The Airstream uses the same helmet but has the filters and fan motor in the helmet, with the battery pack worn on your belt.

Airstream: http://www.airwareamerica.com/3m-hepa-as-400lbc-airstream-hepa-system.aspx

Thanks, but I'll have to save up for that one!

got a used on with 2 batterys and belt , hose, and helmet
will take 200 for it
let me know

ddt, that thing is awesome! I can breathe again......
Thanks