You misread my post. Joebob charges $56 for the cantilever RRA scope mount:
http://www.joeboboutfitters.com/Rock...ra-ar0130t.htm
$90 is the minimum order to get free shipping. Now if RRA provides free shipping on all order sizes and you don't need anything else, then ordering direct from RRA might make more sense.
They are very similar, but the SSALT mounts are all 30mm mounts and they come with 1" inserts (which work very well). I have both and will probably order another SSALT if I need another non-QD AR mount.I had never heard of the SSALT mount before:
It looks absolutely identical to a Burris PEPR (non-QD version).