RAM is where apps run, not where they're installed. You can install apps until you have about 500MB of storage left. If a RAM is too large to run in 1GB of RAM, it won't run, even if it's the only app installed. If the app is small enough to run in 1GB of RAM, you can have a few hundred apps installed. (I think the maximum number of apps I've ever had installed in internal storage was close to 300. That's less than 1/3 of the apps I have backed up on my PC and cloud accounts.)