Yeah key words there are "do the work yourself"
I priced a few swaps and LS swaps started a $16k for a 5.3 and $18k for a 6.0, but that's for a new crate motor too. I would have a problem throwing a junkyard motor and trans into a brand new JK, and I am sure it would be a nightmare getting it to pass emissions "with me doing the work myself" haha