50 Quart Rubbermaid Cooler. Note: from what I gather, this does not have a drain. If you were looking to convert it to a mash tun, you would have to drill a drain hole. Otherwise, it would make a nice cooler to keep your homebrew and more cold.
Related: If you’re looking for larger freezer packs to keep beer and such cold in your cooler, check out Cooler Shock Gel Packs. In my opinion… those are amazing.
As of this posting, Home Depot has this cooler marked down to just $14.97. Order online to reserve yours and select in store pickup to skip the shipping charges. Price, shipping and availability can change quickly. Check the product page for up to the minute price and availability.