I picked up a few Sally Girl "Magic Eyeshadows" a while back, at a charming 99¢ each. They had some cute colors and they looked like duochromes but I didn't get my hopes up. Last night while experimenting with eye looks for a wedding I'm going to this weekend, I pulled one out and WOW did it surprise me.
I got a white with blue/purple shift, a lavender with gold shift, a brown with green shift and a coral/orange with cool toned pink shift. On bare skin they're lovely, over primer they glow.
Seriously, this is Urban Decay quality duochrome. It's super visible even on the eye-- I love using the white in the inner corner for a surprise of sheer purple shimmer, it looks ethereal and alien but gentle. The lavender, when swatched, is more gold than purple but you can still see both. The only shade that gave me trouble was the brown, but the green shift stood out much better over primer. The coral is insane, I don't know if I've ever seen a shadow quite like that. I haven't figured out how I'm going to use it but I'm in love.
All the shadows have lovely textures, not too dry and stiff or soft and crumbly, and the price tag really gives you no excuse not to try these. I bet when used wet the shift would be even stronger.