500k yen for the illustration and model seems pretty steep, but the chapter presented it as perfectly affordable if not cheap. I wonder what's the truth. I wouldn't really know. A freelance (3D) artist is a private entrepreneur as opposed to someone on a game studio payroll. A lot more to worry about and work doesn't just automatically appear on their desk, they need to market themselves and find customers. That being said, 500k yen is a lot of money and there are a lot of people with suitable skills. In the end, game modding communities and fanart communities produce vast amounts of material for absolutely free. I imagine offering some hobbyist 100k yen would have got them extremely excited.
The same 500k for the PC+basic equipment seems reasonable if it's a powerful PC, a quality screen+mic, and such, plus he ought to need a couple of software licenses as well.