Add S3 Infrequent Access calculator.

README.md

@@ -579,7 +579,7 @@ S3
 	-	Deletes are free.
 -	**S3 Reduced Redundancy and Infrequent Access:** Most people use the Standard storage class in S3, but are other storage classes with lower cost:
 	-	[Reduced Redundancy Storage (RRS)](https://aws.amazon.com/s3/reduced-redundancy/) has lower durability (99.99%, so just four nines). That is, there’s a small chance you’ll lose data. For some data sets where data has value in a statistical way (losing say half a percent of your objects isn’t a big deal) this is a reasonable trade-off.
-	-	[Infrequent Access (IA)](https://aws.amazon.com/s3/storage-classes/#Infrequent_Access) lets you get cheaper storage in exchange for more expensive access. This is great for archives like logs you already processed, but might want to look at later.
+	-	[Infrequent Access (IA)](https://aws.amazon.com/s3/storage-classes/#Infrequent_Access) lets you get cheaper storage in exchange for more expensive access. This is great for archives like logs you already processed, but might want to look at later. To get an idea of the cost savings when using Infrequent Access (IA), you can use this [S3 Infrequent Access Calculator](http://www.gulamshakir.com/apps/s3calc/index.html) .
 	-	[Glacier](#glacier) is a third alternative discussed as a separate product.
 	-	See [the comparison table](#storage-durability-availability-and-price).
 -	⏱**Performance:** Maximizing S3 performance means improving overall throughput in terms of bandwidth and number of operations per second.