I am unable to afford a dedicated server at the current time. So I was wondering if it’s OK or advisable to use the Unity master server for a production game release? The docs seem to IMPLY that’s OK and people are doing it. Thoughts?
A pretty clear no, don’t do it.
The server has no uptime guarantee and with your game relying on it, you are asking for trouble as you have no possibility to get it up again.
Also, can’t afford can not really be the case as 11 and alike offer virtual dedicated machines, that are more than enough for the purpose, at $20-30 a month and alike, you don’t need a $100+ / month real dedicated machine 
OK thanks Dreamora that’s fair warning. I was unaware that dedicated Linux hosts were available for so little! Need to do more research.
Do you recommend 1and1.com? Any others you can think of?
I have only limited experience with 11 but Zumwalt has posted on that matter and I think he has had his own masterserver + nat facilitator etc running on them perfectly fine for beyond a year now on the middle vdedicated offer.
depending on how many users you are expecting, vpsland.com can be an option, they are even cheaper, but the power is also considerably more limited
Mindlube, I have a windows server with root access for $9.99/mo from here: http://www.ucvhost.com/VPS/EntryLevelVPS/EntryLevelVps.aspx and I use the package that Zumwalt put together, it works great
The master server doesn’t require much horsepower, and I’ve never experienced any downtime to my knowledge.
legend411 - How is ucvhost doing? I hear those servers are in Africa ? Just wondering the latency / impact is for users in the US. I was looking at http://www.vpsland.com/window_vps_plans.php and Virtual Private Servers - Reliable Hosting Services each have perks for space ram and bandwidth. I don’t know what photon requires since on the topic of windows.
Also added Cheap VPS - SSD Linux VPS and SSD Windows VPS Hosting & Xen VPS - Virpus.com but only ‘the cloud’ offerings has windows.