Yeah, the cabin air-filters are starting to show up at most auto parts stores these days. A year or two ago, if you asked for one you'd get the 'ol blank-stare, mouth hanging open, eye's blinking kinda reaction

. Then they were typically a dealer/order item. IIRC, the last one I bought was for a 1997 buick century, and it was like $19 at a dealer. They do last a long time, but should be changed out every 3yrs or so.
G/luck
Joel