Aha.
Kenny:
I think I have the exact smae model you had. Maybe slightly bigger, it's kinda flat and has three pleated filters set into the front wchich is covered my a lattice door.
I paid like $150 so I might have the next bigger model. I just got it a few weeks ago so no replacements yet...I only use it a few hours per week though.
Rod:
I would NOT go with an ionic purifier. Consumer reports did not rate them highly. HEPA is the way to go and yes there's going to be a cost. I think air purifiers are like printers, they make more money on the filters (in kcartridges) than on the original unit.
Finally Rod one thing you can think about is putting a 3M Filtrete filter in your furnace/AC and just running that all the time. Make sure that the filter is placed in a manner that cleans all air coming through (might need some modifications, most A/C Filters are pretty loose) and those babies will clean your house like nothing else!
That's what I use and when I ran my fan for like 24 hours one the whoel house just smelled better and I had less allergies and stuff. It can get expensive though, electricity wise.
Just some more food for thought bro
Later
JC