Just let it heal for a couple of weeks then plant in the gritty mix. Don't bother to water until roots have developed. You don't need rooting hormone as these root easily.

As to price, I would think these are rather common but I am not in your part of the world. If I had one, I would probably look to give it away to get rid of it. On the other hand, I have now started to sell opuntia pads rather than chop them up to dispose of them when cutting back the plant. It is surprising what demand there is for common cacti. I guess people have to get them from somewhere and garden centres do not often stock the common ones in our part of the world. Check on eBay for how much people are wanting. You are liimited to selling them locally as it would not be practical to package it up to send away.

I would use a garden fork under the cutting to shift it, balancing it on the fork.