For those example props, I'd say 100 - 1000 dollars is about right, depending on volume of work. A single elaborate fountain might be close to 1k$, but with a contract to do 20 or so of them, 500$ per elaborate asset might be fine, since there would be some reuse of decorative bits and there would be a streamlined…
When I was doing freelance before working @ Threewave I'd make/charge anywhere from $100-1000 depending on the prop. A bicycle model used in an action/adventure game, for example, landed me with +$350. It was around 600 triangles, 512x texture space and I only had a couple days to get it and a few other props done. That…
A lot of experienced contractors will handle billing something like this: Figure out hourly rate. For example, say $60/hour. (could be lower or higher). Next, estimate time that it will take to make the object in question. (You should really know what you are doing here.) At a glance, I'd say those simple props would take…