Plan9 is like ocean yacht racing. If you have to ask about the "cost" you aren't the target market.

Plan9 is like writing. You either do it, or talk about doing it. I'm talking not doing btw. I tried, but I got stuck on trivial things and the barrier to asking for help over 2+2= is high. (No offence intended. The 9 heads aren't interested in running a kindergarden)