Por si algún profe quiere investigar sobre estas 70 apps y ver si le son de utlidad. Yo uso algunas // The 70 Best Apps For Teachers And Students - Edudemic. These are listed as itunes apps, but I'm sure a lot of them can be found for Android as well.
24 Smartphone Apps That Pay You - There is no shortage of ways to earn money with your smartphone! You can do mystery shopping, short tasks, and even earn from your shopping trips thanks to all the different apps that are coming out.