Hello, whenever you have apps crashing most likely you have a corrupt app, the lack of storage, or either your gmail account has been changed.
1. uninstall then reinstall the app
2. if option 1 doesnt work, clear some cache or date by going into your setting then app manager. Sort the apps in order by file size (press menu key) then choose an app that you personally installed to ensure that preloaded apps are not tampered with. Check to see if app crashes
3. If option 2 doesnt work, go to play.google.com to log in mainly to make sure you know the username and password. Once this is verified, go ahead and remove the gmail account. This may require a factory reset so make sure you have contacts, calenders, and photos backed up somewhere. Go to privacy in setting and factory reset the device. Once the device has been reset, sync everything back most importantly gmail then try downloading app.
This will work 99% of the time or else the device needs to be replaced