If you are on a limited budget, your best bet is this 1901 Trench. It's a wonderful item, while not very expensive. Another strong contender for your wardrobe is this Scotch & Soda Trench. While the price of this item is not very high, it will definitely attract a lot of attention. Or you can opt for this BLANKNYC Trench. This item has all the potential to become a powerful player in your wardrobe.
If you're looking at it like an investment piece, then you won't be disappointed if you check out this Etro Trenchcoat. It's an expensive but smart option. While you're at it, also have a look at this Loewe Trench Coat. Yes, this item is expensive, but it does not mean it's not worth it. You might also be interested in this Nili Lotan Trench. You won't regret the money spent!