Coolers are an ideal budget solution to cigar storage. But I am an advocate of smaller coolers. 48-50qt coolers are easily stackable in a closet and it gives the ability to separate and expand as your collection grows. Smaller coolers are also easier to move around.
I would also recommend getting a small 70-100ct desktop humidor($50-75) for singles storage and for everyday smoking. Beads are the way to go. I use 65% Heartfelt beads, you'll need about 1/2 pound per 48qt cooler. If you find you prefer some smokes at a bit higher Rh, the smaller coolers will allow you to use a higher humidity in a separate cooler.
