We decided we needed a walk-in cooler for our veggies & glads.
We bought some 2" foam, a $75 window air conditioner. Built a 4'x4' area to the ceiling in our shop. Stuck the air conditioner in the side wall. Had to modify the unit a little. My son did that. He used a themostat off of one of the greenhouse fans. He has the thing cooling our stuff down to 48º.
Whole thing cost us about $125.