My Pokémon history is simply 1st and 2nd gen. I have Yellow and Crystal. I have not played any Pokémon game in years. But this game, WOW! I was able to go out today so I downloaded it to my Android phone and right away I was able to do lots of stuff!
I have Pokéstops (places where you can get extra items/supplies) about a half mile north and south of me. You just have to walk/drive to the locations, and when you're close, you tap the area on your map and spin the photo disc that appears to receive your items (Pokéballs, eggs, revives, etc.).
There are also gyms available one you reach level 5. These are also in real world locations, and you can study under another team trainer and also leave your Pokemon there to battle.
The best part of the game is just by walking around, wild Pokémon are everywhere. I have caught many so far. There is also an Incense item that attracts Pokémon to your current area for 30 minutes.
Please note that this is a new game and I don't know everything about what it has to offer yet, but for absolutely free I have not yet had to make any purchases, I visited around 10-15 Pokéstops and was able to get over 100 Pokéballs from those and from leveling up. Plus, it uses VERY little data, if you have a limited amount per month. It's a lot of fun and you should try it!
Below are some screenshots from my phone of some of the most unusual Pokéstops you may find around your area. Many of them are in certain landmarks.
Please share your Pokéstops and game experiences here!