Error in Play Store: Insufficient storage available
this is   what i learned from my old 1gb app storage phone. To stop notification of insufficiant storage.


clear cache found in setting>storage>internal memory cache.
your phone needed some least amount of memory to work(hide notification) which was 150~200mb for me.Try to maintain the storage of 250mb reserved.
deleting google play not works.Deleting play service may give you some memory but you will need play service.

if still getting the notification at app install just remove your gmail account and untinstall play store (not play service) to factory version then reinstall/update play store and add account.