You have a limited amount of free storage on your Google Drive account, and you can always buy more storage. To see and check used storage on Google Drive in Android and see how much storage left, do as follows
1. Open "Google Drive"
2. Go to "Settings" (on Samsung Galaxy devices you need to tap Menu Button)
3. Scroll down and find "Storage"
4. There you should see a message like this: You are currently using 7.2 GB (48%) of your 15.0 GB. (This storage is for your entire Google services you use in all your devices associated with the same Google Account)