This may sound disgusting, but I am a trash digger! Not like a bum who picks literal trash.
I am talking that I like to sometimes go to the junkyard and see if anyone has thrown out fully working car parts and other types of equipment.
One thing I have really struck gold on was finding a lot of heating and air conditioning products that were perfectly working. Sometimes even finding heating and air conditioning products that were brand new! Mostly portable heating and air conditioning products is what I was finding. It seemed that a lot of heating and cooling warehouses throw out old back stock of portable space heaters, portable air conditioning systems and portable air purification systems. If they had been sitting there for over a year they just throw them out! How crazy is that! I found this out while talking to one of the workers at the junkyard I go and pick through. They know me well over there and allow me to come in and shift through the heating and air conditioning equipment and car parts that all these warehouses are throwing away. With the car parts I take them and keep them in my garage in case I ever need them. With the heat and a/c products that I find, I keep some of them and then some I try to resell after I clean them up. Sometimes, trash digging just brings good things! I suggest trying it if you can! You will not regret it one bit.
AC filter