The most common and cheapest 912uls is not on the list. If we take the cheapest on the list and divide by 2000 hours it comes to $27 per hour, good value for a commercial operator. how cheap do you want it? Remember liability insurance and other costs associated with aviation would not be cheap.
The good thing for home builders is the good supply of very good used ex flying school engines at very reasonable prices, $5k.
The most expensive engine on the list, the 916, which would be very very nice in my RV6a is comparable in price to a new experimental lycoming o-320 160Hp engine. You get what you pay for.