Google is unifying the storage space across its Gmail, Google Drive and Google + products, giving all users access to a combined 15GB of data to use as they wish.
Google Drive was launched last year and up until now, has offered 5GB of free storage. Combining it with the 10GB of storage already attached to Gmail gives users more freedom as to how they utilize their storage.
Unfortunately, with this move, Google has also removed its 25GB extended storage upgrade tier, which was previously offered for US$2.49 a month. The cheapest extended storage option is now 100GB for US$4.99 a month.
Source: Gmail Blog