The price of storage keeps tumbling. As technology becomes more effective, both in terms of end product and in terms of production, the price comes down. Also, new technologies and paradigms are further decreasing the price of storing bits.
Google, as an example, is charging as of July 2014 0.026 per GB in the Cloud, that is one TB of storage cost 26$ (but you can opt for a cheaper option at 20$ per TB).
It is sobering to remember that in 1981 Creative Computing Magazine in its December issue on page 6 declared: it won't be long before we will be able to buy 128KB of storage for just 100$. That price would mean 800,000$ per GB! Looking at today's (2014) price we see a decrease of 40 million times!
Flash memory keeps progressing at a faster speed than magnetic storage, although this latter remains the cheapest form of storage. The interest for flash is tied to its speed and better resilience and durability. In 2014 flash memory is based on 17nm technology with planar chip (2D). By 2016 the technology will move to 32 nm (worse!) but will be based on 3D thus increasing the per chip capacity and decreasing the price. For comparison the average capacity in 2014 is 64GB hilst in 2016 it will be 128GB with a corresponding price per GB decreasing from 0.233$ to 0.108$. By 2021 production will still be based on 3D technology but at 28nm to decrease further in 2026 to 18nm with an average capacity per chip of 2TB (512 GB in 2021). That will bring the price per GB down to 0.018$ in 2021 and 0.005$ in 2026 (estimates from the IEEE Consumer Society and Solid State Circuits Society).
0.005$ per GB, 5$ per TB, is 5 times cheaper than storing on the Google Cloud in 2014. Of course in ten years time it will be way cheaper to store in the cloud than today but still it shows the potential of storing data at very low price in your hand.
Cloud is becoming a way for storing data but it is more a supplemental way than the only way. It is not, yet, leading local storage into oblivion. The recent case of Nirvanix major Cloud storage service founded in 2007 calls for caution! It was able to attract a significant biz from both private and biz customers (including IBM) and in October 2013 just announced that its biz was no longer sustainable and it gave its customers 2 weeks (then extended to one month) to move their data somewhere else. It may not be a coincidence that IBM has released in December 2013 InterCloud Storage service, a way to migrate from one cloud to another in a seamless way all your data!
Magnetic data storage keeps decreasing in price and increasing in capacity, having reached in April 2014 0.035$ per GB (only a bit more than the cost on the Cloud by Google).
Still no end to evolution and price tumbling in sight. And that is good since we are producing and storing even more data at an accelerated pace. I have seen my data storage for digital photo doubling every year over the last 10 years and I guess I am a typical user, noting fancy. Problem is, I've still got 2 eyes only and only about that much time to look at y photo. Technology keeps up, I definitely not!