If you're looking for a bargain, consider buying this Alexander Wang Carryall. While the price is very reasonable, this piece is an easy wardrobe update. Why not also consider this Thakoon Holdall. It's an attractive option both price and quality-wise.
If you want to splurge, then you won't be disappointed if you check out this Proenza Schouler Holdall. It's an expensive but smart option. While you're at it, also have a look at this Jil Sander Duffle Bag. Yes, this item is expensive, but it does not mean it's not worth it.