I've written a few blogs on barcoding and for details readers should refer to them. In short you will need to barcode your game if you want to enter distribution, sell in shops or on certain on-line retailers such as Amazon. While you can generate code images for free, to cover your code against overlap will require you to register and pay a yearly fee with your local arm of GS1. Two alternative approaches have caused some confusion with this concept, QR codes and ISBN numbers and it is to clarify their position that I'm posting this blog.
While a barcode is able to store information equivalent to around 13-18 numbers, depending on your product and region, QR codes can hold information that while not unlimited is enough to practically be so. For this reason the odds of QR codes overlapping by chance is incredibly small. Therefore some producers feel QR codes should replace barcodes, while it is possible that QR codes are the future there are a few reasons that they are not currently a replacement for barcodes.
Number one is that the vast majority of stores simply just do not support QR codes. Given that the only reason to code at all is to facilitate being stocked in stores, adopting an unsupported format on the basis that it should be used is largely self-destructive. China is beginning to support QR codes on store sold goods but as yet they have failed to make headway in Europe or America. It may be that China's industrial strength will drive QR codes into wider usage but it is far from certain that practices which have penetrated their more centralised markets will achieve similar results else where and certainly too early to rely on them now. Fundamentally this is an area where being ahead of the pack has no advantage.
The second issue with QR codes is that while being able to convert almost any information into a QR code offers a theoretically huge range of options practically, many products have similar or identical names or titles and so will still suffer overlap. When you allow people to pick anything they like they have a tendency to all pick the same thing. There is currently no accepted format for QR codes and not all independent producers will have either a registered company name or their own website domain name. Additionally, if the accepted format for QR codes becomes, for example, website domains it stands to reason that the cost of registering and maintaining a domain name will simply increase as its commercial purpose extends. In short at this point QR codes are unsupported as a replacement for barcodes and have no settled commercial format leaving them some distance away from being a direct replacement of barcodes. At best they are a secondary or support format.
Somewhat more confusing and problematic are barcodes based upon ISBN numbers. A barcode is a set of numbers rendered in scanner readable graphical form. There are two commonly available methods of generating a supported registered number from which to generate this image for effective distribution: either by paying to register with GS1 or by paying for a single ISBN number (International Standard Book Number). ISBN numbers can be purchased one at a time from their official provider while barcodes need to be purchased in blocks of 100 (see Barcoding For Independent Designers: Clarity and Legality). As such while a single barcode when you are using 100 is much cheaper than a single ISBN number, a single ISBN number is much cheaper than 100 barcodes. This has led some publishers to attach ISBN based barcodes to their games. The guidelines for appropriate usage of an ISBN number are necessarily loose, they don't rule out a book from being a book just because it includes certain peripheral items. So if you are selling a book on playing the mouth organ with a free mouth organ it counts as a book. However, if you were to sell a flat pack cupboard with a set of instructions, even if the instructions are as thick as a book, it wouldn't count as a book. The line between one and the other is extremely vague but it is unlikely to be true that your boardgame is a manual with some bits attached, at least one would hope.
The fact that the spirit of the law is against it is far from enough to discourage some publishers however it should be considered that many countries zero rate books for tax purposes. As such it could be viewed by your local tax authority that a decision to use an ISBN number for the registration of your boardgame is the first step in an attempt to avoid taxation. While the authorities have no legal power to stop you from breaching the spirit of the law in relation to ISBN numbers, the tax man can put you through a long and expensive audit for nothing more than misclassification.
Once again, barcodes are the industry standard and GS1 is its official method of registration. There are a range of loop holes and short cuts to avoid paying for GS1 registration but all of them come with inherent problems, arguably more than the cost of registration.