For something in the middle of the price range, why not take a look at this Marni Skirt. While the price is very reasonable, this piece is an easy wardrobe update. You might also want to consider this Marni Midi Skirt. It's an attractive option both price and quality-wise.
If you can afford it, then you absolutely must check out this Marni Pencil Skirt. This product seems expensive, but it's worth it. Another product we're drooling over is this Marni A-Line Skirt. It's pricey but you get what you pay for.