For something in the middle of the price range, we recommend considering this Gucci Holdall. While the price is very reasonable, this item is an easy wardrobe update.
If you can afford it, then what you're looking for is this Gucci Duffle Bag. It's more expensive but worth your money. While you're at it, also have a look at this Gucci Carryall. Yes, this item is expensive, but it does not mean it's not worth it.