Winix D360 HEPA Air Purifier - up to 360 square feet room - $25 (Lacey)

Perfect for allergies: filters out allergens like smoke and pollen from your room air.
This is a couple of years old.
There are two new charcoal foam filter sheets included.
The replaceable HEPA filter is still good.
Replacements on Amazon and other sites are around $20.