While I have no way of knowing if the pictured receipt is legitimate, I have heard from various servers and wait staff that what you say is true. (redeeminggod.com)
The numerous mods that can be played on various servers is what is truly makes the game and has literally kept the game alive for years. (metacritic.com)
You can explore alone, go with a buddy in local multiplayer, or join various servers with different rule sets with both official and private server options. (videochums.com)