If you were to buy 135Tb on Amazon EC2/EBS the same capacity would cost you ~$19,000 per month, not counting charges for I/O and bandwidth.
Still, way cheaper than Amazon, but there are nontrivial running costs beyond the purchase and build price.
If 100 TB was as easy as buying a bunch of discs and slapping NASlite or FreeNAS on them then everyone would be doing it.
S3, economically speaking, is an incredible deal if you are only using a little. But if you are using a lot? it makes NetApp or EMC start to look good, which is to say, only a good deal if money doesn't matter.
I mean, yeah, if you are in a situation where money doesn't matter, or rather a situation where the amount of money you are spending on the storage is trivial compared to what you are doing with the storage, sure, NetApp or EMC will deliver a far superior product. S3 may have it's uses too. But if you are doing something where the storage needs to be cheap? yeah, neither one of those players, nor S3 will get you where you want to go.