A barcode, or UPC code, is essential if you’re planning to sell your CDs in stores or online. 
Each product has a unique 12-digit number encoded in the bars, which are scanned upon purchase to track inventory and sales.
Getting a barcode
As a special service I can provide you with a UPC barcode number free of charge when I do your design. This UPC will be unique to your project, but will not be registered to you. This is quite adequate and appropriate if you are just releasing a few records. However, if you are trying to run a real record label, and intend on releasing many records over time, then you will need to invest in your own barcode.
To get your own barcode, you must join the Uniform Code Council: www.uc-council.org. The current price is about $750 I think.
Special software is needed to generate the barcode. I can do that for you if you need it.
Soundscan
Nielsen SoundScan collects weekly sales data from 14,000+ retail outlets in the U.S. and Canada, which are published on their site and in the Billboard charts. If you receive a barcode from Crescent Music Services or other manufacturer and you want your release tracked by SoundScan, you will need to change the barcode registration to you, the recording artist, as a sub-label. To do this, download the Title Addition Sheet from www.soundscan.com. The Title Addition Sheet must be submitted to SoundScan’s Database Department by email at dbase@soundscan.com or faxed to (914) 684-5606.
You can also subscribe to SoundScan’s reporting service for a fee. CDs sold at gigs or from small stores do not normally get tracked by Soundscan unless you are a paid member, SoundScan does allow artists that tour to report these tour sales to Soundscan as venue sales.The actual reporting process is very easy, once you are set up: calculate the venue sales, get the venue to sign off on the sales, and then fax the info to SoundScan.It’s part of the reason that Prince’s idea to give away his Musicology CD a few years back was such a great idea.The price of the CD was included in the price of the ticket, and all sales counted towards SoundScan – which cumulated in great Billboard visibility, which gave him more press, which drew more people to his show and made more people buy the CD etc.
In case you’re interested in joining, the last I learned about the fees and procedures sounded unteneble for most indies: 1. On letterhead of the label, please state that you are a label interested in taking part in the Venue Sales Program. Also state how long you have been in business. NOTE: YOU MUST BE IN BUSINESS FOR AT LEAST TWO YEARS. 2. List the artists you wish to report sales for. NOTE: IT MUST BE MORE THAN ONE ARTIST UNDER THE LABEL THAT YOU WILL BE REPORTING SALES FOR. 3. Fax the above information or email. 4. There will be a $500.00 annual fee to report venue sales. Acceptable methods of payment are: Company Check & Credit Card. *Please include in the letter that you fully understand that you will be charged this annual fee and your method of payment.* 5. Please provide name, billing address, phone number, fax number and email to receive proper mailing and billing instructions. 6. You will then be contacted to set up an account to report and transmit sales along with proper documentation to verify all sales.
Never mind.
Anatomy of a Barcode
Reading from left to right, 12 total numbers:
Digits 1-6: your company ID number assigned by the UCC. Digits 7-10: release number, assigned by you. Digit 11: configuration digit (2 = CD, 4 = cassette, 1 = vinyl LP, etc.). Digit 12: check digit, formulated by the computer when the barcode is generated. This is used by the scanner to confirm that it read the barcode correctly.