Okay this one proves that Best Bang for buck is 16GB followed by 64GB and than 32GB of i4S
https://www.macrumors.com/2011/10/20/iphone-4s-component-costs-once-again-begin-at-about-188/
In the case of the iPhone 4S, [IHS iSuppli analyst Andrew] Rassweiler estimates that the BOM cost ranges from $188 for the 16 gigabyte version of the iPhone 4S to $207 for the 32GB version and $245 for the 64GB version. Apple and its carrier partners sell the phones for $199, $299 and $399 respectively, typically with a two-year contract for wireless service that carriers use to subsidize the cost they pay Apple.
https://www.macrumors.com/2011/10/20/iphone-4s-component-costs-once-again-begin-at-about-188/
In the case of the iPhone 4S, [IHS iSuppli analyst Andrew] Rassweiler estimates that the BOM cost ranges from $188 for the 16 gigabyte version of the iPhone 4S to $207 for the 32GB version and $245 for the 64GB version. Apple and its carrier partners sell the phones for $199, $299 and $399 respectively, typically with a two-year contract for wireless service that carriers use to subsidize the cost they pay Apple.