Do funeral homes re-use coffins ?

No. The coffin is buried with the body in it.

Nothing more needs be said

I’ve worked in the funeral industry, and I assure you, it could never and would never happen.

Even really cheap, filing-cabinet-metal grade coffins (in the U.S. they are caskets) can be made to look decent at a viewing with flowers and embellishments.

Even if they do the body inside wouldn’t notice..)

No. The family pays for a coffin. To not use it would constitute fraud.

I have heard of this when cremation is going to happen, they have the body in a coffin for the funeral then after that I think it would be reused but in those circumstances I don’t think the family is required to buy the coffin.

It probably depends on the jurisdiction. I believe it’s illegal in at least some states.

@Darth_Algar is correct. Some states allow you to rent a casket for a viewing and then have a cremation. I believe they use a disposable liner.

Uh @Darth_Algar didn’t say that I did!