This particular batting cage is not meant to be cemented into the ground. It has legs that splay out and people normally use tie-downs and stake it into grass for added stability. That said. I supposed it would be possible to do the same thing with buckets of sand.
The best solution would be to get the correct batting cage for what you want, which is the Cimarron 55'L x 15.5' W x 12' H Complete Permanent Commercial Batting Cage. It has ground sleeves which are cemented into the ground and it sits on straight poles that slide into those sleeves.
You might also consider the less expensive KIT version of that cage - Cimarron 55'L x 15.5' W x 12' H Permanent Commercial Batting Cage Kit. You just have to pick up the metal conduit poles at Home Depot, but even after purchasing those, you would save more than $300 versus purchasing the complete frame, poles and net kit.
Finally, if you have your own net and just need the frame, you would want either the Cimarron 55x15.5x12 Complete Commercial Batting Cage Frame which includes the poles, or the KIT version, where you purchase the poles yourself and save money - Cimarron 55x15.5x12 Commercial Frame Corner Kit.