Not cheap, but helps with 10% off code. I dont think they have sales often. Good time to get replacement filter's if you need them. Most of those with free postage.
If you do get a purifier I suggest you buy a few prefilters. The main filters last alot longer, but they suggest the prefilters last about 3 to 6months. Really depends on your air quality. I haven't replaced mine for about 9half months.
Australian designed and manufactured.