I have a new sealed box canister housing water filter system kit, which includes the mounting bracket, filter change wrench and your first filter. These or similar kits sold by several manufacturers are often called, "big blue" systems.
No damage or anything. Very clean box, no box damage either. I have some access to some plumbing supplies from time to time and sell the items I don't have a need for myself.
$40 FIRM. These tend to sell for at least $75.
The blue filter housing canister system on the left one takes filters sized approximately 4.5 inches wide x 9.75 inches
This one includes two sediment filters, wall bracket and filter wrench.
This is an ideal product to purchase on Craigslist because unlike electronics, there's nothing that can go wrong or malfunction. It's just a screw-on cap with canister, a filter and a wrench.