The costs for an injection moulded product can be reduced by analyzing whether and to what extent the most economically attractive raw material can be used while still meeting the functionality. Secondly, it is always advisable to save as much material as possible by making the wall thickness as thin as possible. This has the additional advantage that the process time is also reduced. Thirdly, it is advisable to let several products come out of the mould.
Finally, injection moulding is a mass production process and the standard cost parameters can be minimized by maximizing the batch size and minimizing colour combinations. However, be realistic and base numbers on some facts.