Not a suggestion to a specific duvet cover but if you sew you could find 2 king sized flat sheets with a similar pattern and make your own

Thoms O'Brien for Target had something very similar a year or two ago, and it was navy blue. Try eBay. Overstock also carries a lot of Moroccan-inspired patterns.

I found this on Overstock. It is a duvet cover, so you would have to provide your own comforter. Shouldn't be a problem. Here's the link:

http://www.overstock.com/Bedding-Bath/Lyon-Duvet-Cover-Set/6423955/product.html

I think that Florida Joyce has hit the nail on the head for you, under $40 for a king cover set.

For the comforter... I actually like the Mysa Ronn down comforter I got at Ikea years ago. I've washed it in the washing machine a few times and it's still lovely. http://www.ikea.com/us/en/catalog/products/60133498/

West Elm has great, inexpensive duvets. Though they're not exactly like what you found, you may find something to compromise on there.

My advice is to work, save up and get the one your really want.

Rue La La is a flash-sale website that regularly features duvet sets and other bedding. They have new sales every day, with each sale lasting 2-3 days. I highly recommend checking it out.

ruelala.com

I am with TESSYPIE, West Elm has great duvets. The styles change every couple of months, so there is always something on sale. And right now they are transitioning from a Indian/North African theme to South African, so you might be able to find a pattern similar to what you are looking for on sale.

Here's one in midnight: http://www.linenplace.com/products/Bedding/Duvet-Covers/Quatrefoil.html

$99 bucks.

Burlington Coat Factory had a navy/white and grey/white version of that trellis print in some stores. Of course since selection in stores always varies it depends on your luck!

This is more true blue than navy but is a good price and is great quality: http://www.landsend.com/pp/200-count-chain-link-duvet-cover-or-sham~236069_1098.html

I'm looking for that same pattern in yellow! However, I feel like I've seen others in a dark color by googling navy quatrefoil duvet

I was lusting after a $150 duvet cover at Z Gallerie last year that NEVER went on sale. I just wasn't going to spend that much on something my cat was going to lay on all day. Anyway, I looked at it everytime I was there, only to find one day that it wasn't on display anymore, so I figured it was long gone. Til I found it on the clearance rack for 60% off! Booya! Seriously felt like the biggest victory. Which I realize is sad. But anyway, patience (or you know, giving up and being surprised later) was totally worth it ;)

Since you've already gotten a lot of useful comments, I guess it's okay for me to point out that "duvet" is a comforter cover. "Duvet cover" is redundant :D Even sellers make that mistake though so I understand why it's catching on!

I bought the duvet listed above from overstock, it's a great knock off and so inexpensive. My only complaint is that it's not as soft as I would have liked but besides that it's great!

@tonia329, a duvet is a comforter. A duvet cover goes over a duvet.

Make one by sewing two sheets together!

I vote - save up and buy the one that you love. I used to buy the cheap versions of things, but would live miserably with them for a relatively short time, when I could not stand it aymore I would replace with something else cheap, and then repeat the cycle all over again. After going through pretty, but scratchy Ikea sets every 4- to 6 months for a couple of years, I purchased a nice soft Crate and Barrel set, and have been living happily with it for the past 2 years. Yes, it cost 5 times as much to start, but I've enjoyed living with it, and I am now happily in the saving money by not having to replace it zone!

I second the rec for the Lands End duvet cover, if you're open to a slight shift in pattern.

That said, if that's an option for you, saving up and getting the one you really want may be the best choice, assuming the exact design/color will make you happier.

http://www.amazon.com/Echelon-Quatrefoil-Queen-Duvet-Midnight/dp/B004LLHPIE/ref=pd_sim_sbs_hg_2

I don't know what exactly they have right now, but IKEA has beautiful duvets and covers at good prices. Their covers are cotton, which is immeasurably nicer than the microfiber most covers are made with.

I found this one on Amazon in a few colors, though not navy.
http://www.amazon.com/s/ref=sr_nr_n_2?rh=n%3A1055398%2Ck%3Acharleston%2Cn%3A!1063498%2Cn%3A1063252%2Cn%3A2224404011&bbn=1063252&keywords=charleston&ie=UTF8&qid=1347656146&rnid=1063252

Duvet covers are the easiest possible sewing project imaginable. Instead of buying the duvet cover, buy two flat sheets (or if those are ridiculously overpriced as well, go to a fabric store and find a pattern there that works for you both). You just take big flat rectangles in the size you pick, and sew their edges together. Leave a slot, hem it, add buttons or ties or velcro or - hell - go wild and lace it like a corset or put buckles on it. Ta da.

we got a great one from lands end same pattern in gray and light blue over cream. I can't have spent more than $50. not sure if you'll still find or if colors will work for you but I love it.

I am slightly addicted to bedding sets. Duvet covers really really help feed this bad habit of mine. I have a few from Overstock. I think Florida Joyce rocked the suggestions!

Spend the money and get the ones you want. Good quality linens last a long time. I was making the bed today and I started thinking about how old my favorite bedding is. I'm embarrassed to say that it's at least 15 years old. We only use it in the summer, so it's been in use half that time. I still love it. I still enjoy changing to the summer sheets every year. Every day when I climb into bed, I admire it. Amortized over that time, the extra you will spend on what you really want is only a few dollars a year.

Totally worth it to have what you want.

I'm going with saving up.
I did that with furniture during our "early American poverty" design era. :)
Basically, I'd buy a sofa or kitchen set on sale and get less than a year öut of it. The microfiber cloth (yuck!) would pill or rip, the arms would get loose and wiggly and the seats would sag. Eventually, I had a couch custom made and then slipcovers custom made on top of it. I've had it about 8 years, it still looks brand new and, most of all, I still look at it and smile.
Sew your own on the cheap with some Kohl's or whatever cheap sheets but spend your money where you'll continue to love it.

Very similar for $99 http://www.target.com/p/lattice-8-piece-bedding-set-navy/-/A-13095403

We got these as part of our registry, although it's mostly white, I think the pattern is a great match:

Echelon Quatrefoil Duvet Cover Set
http://www.amazon.com/Echelon-Quatrefoil-Queen-Duvet-Peacock/dp/B004LLHPJ8/ref=wr_it_dp_o_nS_nC?ie=UTF8&colid=18VAGIPDTLH9L&coliid=I1AE1G17GU1BGP

Yes, I agree with the advice to save and get the one you want. I just switched out my bedding to my winter/fall set. I was so happy to unpack the Pottery Barn duvet cover and pillow shams I bought about four years ago. They still look and feel like new!

In terms of saving money, I bought a high-count (600 thread) set at Target during a sale. I think the whole king size set was less than $50. I was worried that the quality would be iffy, but they are really nice, durable sheets.

The highest price on that duvet cover from Z Gallerie is $169. If you are willing to spend $100 then you might as well get the one from Z Gallerie. Wait a bit, save more and go get the original.

Started to look for one at the beginning of summer giving myself time to search everywhere. Low and behold, HomeGoods. $24.99 for a Calvin Klein queen duvet cover in a nice Silver/Grey. Now we are ready for winter. Sometimes limited, but if you keep looking and find out their delivery dates this can help in your search.

I purchased a very similar duvet set from TJ Maxx. It was a few years ago, so I couldn't tell you the brand or how much I spent- but I'm notoriously stingy, so it must have been a good deal. Check TJ Maxx or Marshalls!

http://www.target.com/p/lattice-8-piece-bedding-set-navy/-/A-13095403#?lnk=sc_qi_detaillink