M.2 SSDs with self-encrypting feature

I know the SSD m.2 standard is relatively new.
So perhaps thats why it's hard to find SSDs that have self-encryption feature. (I don't like dealing with Truecrypt or other software solutions).
I did find a Samsung m.2 SSD 512GB with self-encryption, but the price is over $500.
In other formats (mSATA and 2.5), Samsung 520GB drives with self-encryption are far more in line - at about $230.
Wondering when prices will come down on the m.2 version.