I built a rough wood frame out of 2x3s for some solar panels. It's fully exposed to the weather. I would like to paint it with something to protect it, but I'm not sure what the best option is.
For example, I could use deck stain, exterior paint, "barn paint" or something else.
My priorities, in order are:
Cheap
Long lasting
Easy to apply
It doesn't need to look pretty, although it would be nice if it ages gracefully and doesn't get all peely after a couple of years.
What type of coating should I use?