I could save a ton of money on video games if I learned Japanese, considering the import copies tend to be way cheaper than the limited-production English runs of many niche JRPGs.
Depends on the game and how you buy it. In general, buying digital is easier and cheaper in the US, due to more PC releases and aggressive price cuts and sales. Japanese digital stores have much less frequent and less generous sales, and older games don't get their base prices reduced by much.
But if you buy physical copies, then the Japanese market might be cheaper simply due to the greater supply of older games, and potentially the currency conversion of newer games.
Learning Russian just to save money on videogames is a pretty bad strategy when you account for opportunity costs - though I accept people sometimes find great amounts of motivation in silly things.
Another, somewhat depressing, way of looking at it is that we all could have learned half a dozen languages in the time we spend browsing and posting to no real end on forums and various other media such as this. And e.g. learning Russian would make you feel good at the end of it. Whereas when you look back at the years of social media (which, again I would include sites such as this) it all seems like quite a tremendous waste of time. Yeah, we're totally changing the world by expressing and sharing our views, values, and opinions. /s
Another piracy incentive for people who prefer the original over the typically low-effort translation. Even applies when the original is in a third language, the English translation tends to be higher quality (for a multitude of reasons).
Guess it's another instance of "why we can't have nice things".
For example, you can buy a Russian key for 50% off, but it is a Russian version of the game with the audio/text to match.