Unfortunately, this isn't a drugstore available dupe, BUT, it isn't a high end dupe either. The Urban Decay eyeshadow "Deep End" is a new shade UD released in their 15 Year Anniversary palette. In this picture, it's on the bottom row, in the middle.
Now. The palette that I have that contains the somewhat "dupe," I purchased on Ebay. The seller I purchased from is no longer a seller (I paid about $21, two years ago), but it is available from Amazon's Bundle Monster brand. I'm guessing it's the same quality as the palette I have, because the colors are identical, and all the reviews are great.
It's 120 eyeshadows with shimmer, matte, frost, every finish you can imagine.
For $26- this a great deal. I have had this palette for 2 years now, and I still use it all the time. The shade selection is great. It's divided into two trays, this is the bottom tray- which I prefer over the top tray. The shade in the bottom left, and the shade in the bottom row, 4 over from the right, both broke on me (I've moved multiple times, and used to keep my makeup in a bin when I first got this). But the shade in the top row, 4 over from the right, I actually hit pan on that shadow!! It's GREAT. It's a shimmery gunmetal shade- I love that one.
But back to the topic, the shade we're referencing here is the second row, 4 over from the right. It's a metallic turquoise, quite similar to "Deep End."
(The metallics in this palette are so great.)
Top: BM 120 Palette
Bottom: "Deep End" from Urban Decay 15 Year Anniversary Palette
The noticeable difference is "Deep End" is slightly darker, and appears more saturated. But I think Deep End actually has the slightest golden sheen to it, that the BM blue doesn't have.
On the eye though- I'd say they'd pass as pretty close.
You could create similar looks with both, very easily.
In fact, I unintentionally did two similar looks!
This first picture, I used the UD 15 year palette about two weeks ago
For more pictures of this look, Click Here.
I patted "Deep End" over a dark purple on the inner corner, so you can't really see how vibrant it is here.
This second picture, I did this look about 2 years ago when I first got the BM 120 Color palette.
There's some prettyyyy bad editing done here, and my eyebrows were practically non existent at this time, BUT you can see the intensity of the turquoise is quite dupable.