ArchViz Freelancing Resources

Classic freelancing discussion, “what do I charge”?

I have some standard hourly rates playing around in my head that I would translate into either project or daily rates for a potential client, but I just want to confirm I’m not undercharging. Does anyone have a resource of what a freelance archviz project would cost? I can find a lot for graphic design, and I know what I’ve been paid for full-time work in the past, but I want to see if the freelance rates differ significantly. Obviously I’m not factoring in things like the cheap render farms in China that will do a room for $75. Anyone know any websites, blogs or books that may be useful to me?