El Constructorr: I don't know how to mention your special username.
Completely agree with everything you have been able to explain from the start.
Just:
The next one is $95 for 3 months
Nowadays the very first paid plans are one-time for "60 months" (5 years):
- $95 one-time for Photon Realtime (100 CCU, 500 msgs per second per room).
- $45 one-time for Photon Chat (100 CCU, 100 msgs per second per channel).
Beware, one-time is not lifetime.
The free versions offer the same amount of msg/s, which is more than sufficient in terms of bandwidth (see details) with well thought out, coded and called multiplayer patterns. And yes, no need to send player updates to everyone, every time (target in raise events). Finally, no need to tear your brain out with the native Construct plugin or the management of a server, which, it must be admitted, represents a significant amount of additional work, human and technical cost.
- Realtime pricing: photonengine.com/en-US/Realtime/pricing
- Chat pricing: photonengine.com/en-US/Chat/pricing
That said and of course there are pros and cons everywhere (cloud / self-hosted / provider, etc), it is a view of mind and decision-making strategy, not to mention the wallet aspect.
To develop and learn all the concepts, the free plans are already very good and an interesting compromise to test a project.
Some good practices (valid for all multiplayer games):
- Performance tips: doc.photonengine.com/en-US/realtime/current/reference/performance-tips
- MMO concept: doc.photonengine.com/en-us/server/current/applications/mmo/mmo-concept
More informations:
- A Photon blog post about pricing model: blog.photonengine.com/photon-pricing-explained
- Realtime Glossary: doc.photonengine.com/en-US/realtime/current/reference/glossary
- Realtime FAQ: doc.photonengine.com/en-us/realtime/current/troubleshooting/faq
There is a lot of other resources on their website, faqs, documentation, forum...
And 
ThePhotons is often around here. Good luck! :-)