It was just like a surprise on my device with 1GB free storage space and still receiving insufficient storage space while trying to install an app from playstore and also same while trying to use my device Camera but later on I found a solution to this and my download and selfie taking was successful.
How to Fix Not Enough Memory on Installing Apps from Playstore.
1. Go to System Settings and Tap Storage.
There are also sometimes when you would try downloading files and you would receive not enough storage space but you may have free space on other storage. I mostly encounter this using my Camera when my sdcard slot is full so it gives an info to change storage space. To fix this if you also encounter this just:
1. Go to system settings
2. Tap Storage
3. Change Default Write Disk to where you have free space. From above imade I changed my default write disk to Phone Storage just because my SDcard is full.
Feel free to use the comment section to ask any question.