According to analysts, the next-generation iPhone 4 could have a bill of materials costing between $169 to $175. That’s a pretty significant increase from the $156 bill of material cost to manufacture the current iPhone 3GS. These figures are based on estimates of models using 16GB of memory. The cost could get even higher for the 64GB model, estimated at around $250. Apple’s iPhone has been receiving much competition from Google’s Android software and this higher cost of the next generation may pose some trouble for Apple, as they will be entering the field with a gadget much more expensive…