If you realize that your item will be distributed and sold through the usual wholesale or may be the retail channels, you should then definitely consider paying the additional cost for the bar codes. The barcodes that are generally used in sales and marketing come in two different formats- one is the EAN13 and the other is the UPC-A. The first one is common. The second one has the advantage of being readable in most of the places in Europe and USA. But the EAN13 is more generic to the European market.
To all musicians; procedures like mastering, mixing and publishing sound very interesting. Have you all ever realized about there are some terms that are related to music and without them, it is not possible to publish even one single song? Each of the mastering engineer having good knowledge about the terms like Metadata embedding, UPC/EAN codes, QC and ISRC codes. They are very important when you are dealing with sound engineering. Without these codes, no musician can ever bring the music to live.
The final touch to any music track you work on should be its mastering, and in the internet age access to professionals is easier than ever. Music mastering at a commercial quality level is available for all utilizing several online experts who can manage the engineering and mixing of your composition, be it a single or full CD. The richness of sound achievable through proper digital mastering is essential and is an expected part of publishing recordings today. For initial samples you may be able to perform do it yourself mastering, but for competing in the real world, do not neglect using a pro to complete the post production. A poor master can cause the music track to be rejected as amateurish, solely due to defective sound quality.