A K&N filter cleaning kit costs $9 and can be bought at any autozone or pep boys. And it will probably let you clean and oil a filter 10 times.

Or you can mail-order a replacement HKS filter for $15 every 6 to 10kmi.

 

do knn filters come oiled from teh factory... cuz why not just keep replacing the knn filter? it's hardly more expensive than buyin' jdm filter replacements.