do a search for goggles on this board and you will find some more answers but i think as you say, people use goggles when its foggy / snowing and sunnies other times. Although I dont think theres any problem wearing goggles all the time as long as they're tinted.
You could just try and find some cheap shades?
I've ordered some off ebay shops but obviously im not sure of the fitment or quality but they were only a few quid, shipped from the US.
I wore expensive shades boardind last year in Switz. They only came off once and that was cause I bailed and landing on my face. Found them and no damage.
You can get cords that fix them to your head quite cheap