The Core Lokts are around 11$ a box, the SST's are around 10$ a box.

As far as the Mossberg 500 is concerned, there is something unusual about their barrels. I have not heard of one person who has been happy with the performance of sabots out of those barrels. Unfortunately they find rifled slugs to be more accurate.

If you are shooting at close range that is not an issue. However, at ranges beyond 75 yds the trajectory of rifled slugs becomes a unneccesary drawback of their use.