While organizing my single shadows this past weekend, I happened upon Cover Girl's Fire It Up. It looked very familiar, then I finally realized how similar, if not exactly the same as California by NARS (which I got at Sephora for $8 regular price $23). I had gotten the CG shadow on sale last year for $1.50 (I think) or was it one of those I found at the dollar store.
L to R: Cover Girl's Fire It Up and NARS California
Now see if you can tell the difference:
Blended out on my arm (flash)
And the swatches are in the same order as the shadows in the first pic. I could not tell the difference at all.