Can two almost identical apps be uploaded on Apple Store?
Similar apps can be uploaded if your app has (version based app) free, paid or in-app-purchase with clear description of each version of app will minimise the chances of rejection of the app.

Else the app can be rejected by Apple under:


  2.20 Developers "spamming" the App Store with many versions of similar Apps will be removed from the iOS Developer Program


App Store Review Guidelines