we try not to drop them. On occassion, it is unavoidable. They are fairly tough as long as you put a rubber mat down so that they do not hit concrete directly. We have shattered one a while back. That was due to a particular guy who was not very good at stones dropping the stone on concrete many times (outside of my presense obviously). No I'm not talking about you Linder. I gave that stone a final load into the dumpster.
The cost varies depending on how you want to get them. I know King_79 makes them from time to time. We got some of our smaller ones from him. All of our stones were made by pouring concrete into a mold. They range in price from about $.40 per pound to $.80 per lb depending on quality, who you get them from, ect.