Here’s the long answer.
It must totally depend on the funeral home and whereabouts you are. I am in Canada. They never mentioned anything to me about renting a coffin for my husband to be in during the service.
I was actually told that it is becoming more popular or common for people to choose or decide to get cremated instead of being buried. I don’t know if that just a popular choice in my town our at this particular funeral home but I was told that they believe that within about 10 yrs that burial practice may even be almost absolete, they also told me they believe most people now prefer cremation (which is evident by the amount of cremation walls around the place now of course I did not pick the place it is a family plot) instead of burial because it’s cheaper and more eco friendly (their words not mine) but less body takes up less space, less trees being chopped down for coffins and less ground we are digging up etc. That is their opinion.
Before my husband passed away he told me that if something happened to him he wanted to be buried so I honored that. The coffin that we picked out ended up being a fancy coffin that they didn’t showcase in the funeral home, as my husband had big ideas, like he did want his own underground tomb but the funeral home wouldn’t do it (maybe because they are to eco friendly) anyway the coffin was a day late because it was coming from somewhere in the U.S. so when we had the funeral service we did not have my husbands body there.
They did offer a rental casket or cremation urn but it would be without a body or ashes in it and it was just for show. I opted not to do that and just chose to have a memorial. I thought it was outrageous to pay 600$ to rent a box (or an urn, which made no sense anyway since he was not cremated) that was just for looks, besides the casket was not going to be open anyways.