For a print run of over 300 CD-ROM copies, using duplication as a means of reproduction becomes prohibitively expensive. From this point, it makes better economic sense to have the CD-ROMs pressed to industrial standard.
A master CD-ROM with the desired content needs to be created, which incurs a one-off cost. This master is then used to create a precise press mould. This makes it possible to produce as many exact copies of your master CD-ROM as necessary. With this method of production, it is not necessary to pay the price for the respective number of blank CDs, but just a fraction of it.
The higher the print run, the cheaper the unit price.