Just looking, yea the Asus adapter probably the cheapest and best option. Saw another one with ribbon but its just an "extender" meaning the mpcie slot better natively support msata or else you are using the extender for wifi card or whatever the slot is designed for. Its an extender, not an adapter.
Oh and did find a 128GB mpcie ssd for an older Apple I guess. Only a mere $100 shipped. Yep rare bird indeed.
Oh here is one that came with Asus EEE
8GB for $10....