Donkey Kong was just a quarter when it came out. I distinctly remember playing it at roller rinks and arcades and as a poor teenager I wouldn't have been playing it if it was more than that. The first "big" game that was more than that (or maybe the first that was a dollar) was Dragon's Lair. Perhaps this was a local thing, but in my area (suburban Minneapolis, MN, USA) it was a quarter.

The points about communications are huge though. If you didn't grow up during that time you don't understand how different it was just to try to get ahold of somebody at any random time.