Chevis, you are a design professional that is willing to put in the time to guide the student. It really depends on who the client is. When I was leading the in house design team at Sound United I had two approaches. If the project was big enough and required a sustained resource, I would just hire someone in house. If the project was either a gap in available resources or a gap in skill sets but only a temporary thing, I would hire the best design firm possible, and they were charging a lot more than $150hr. More like $300-$400. And for that price what i was getting was full project management, and a guarantee that I could push them as hard as I needed.
I went out of house for renders a lot as well. I used xyz mainly: http://www.xyzgraphics.com Expect to pay $10k-$20k for a suite of excellent renderings that are super high res, use all of the right materials, and can work for print or web.
You always pay for quality. The question is do you want to pay for it once on the front end, or pay for it twice on the back end?