Today there are some adorable light-weight coats/trenches that are under $100. Brand is called lola, which I'm not familiar with, but the cuts are cute and stylish! Pick this ruffled lovely for less than 80 bucks!
Or this muted grape bubble trench for 82 big ones.
I personally have enough grey outwear to sink a ship, but might just need to add that purple pretty to my hall closet.