We do not create the codes, they are delivered by GS1 to companies who don't use them and sell them to us. You do not get your own unique code prefix, which is perfectly fine to sell your products.
The short answer is yes, our codes can be used to create your products on Amazon. You cannot use them for products of existing known brands, books, or pharmaceutical. Do not use our codes if you are going to Amazon brand registry because you will be expected to use the same prefix all the time which we cannot guarantee. We cannot help you if you cannot upload products after choosing to go for brand registry.
You need one code for each product 'variation', such as size and color. For example, 2 t-shirt designs, 5 sizes each and 2 colours each, will require 20 codes (2 * 5 * 2).
You will receive by email UPC-A (12 digits) codes AND EAN-13 (13 digits) codes, both are variant of the same code. Each code is accompanied by graphics of the corresponding barcode.
Our codes will work for all products but books and pharma, but ok for health products such as protein powders, etc.
Absolutely, our codes will work worldwide, online and in retail.
The prefix is simply an indication of which country the barcode originates in but is not at all a condition to sell in a country. GS1 explains "since GS1 member companies can manufacture products anywhere in the world, GS1 prefixes do not identify the country of origin for a given product." We have people using our codes with US prefix to sell in the UK in Waitrose and Debenhams for example, or products "made in France" in France. If someone say they will sell you codes with an UK prefix it will not be legit, as only US companies were once allowed to resell their codes. See also here and here.
We don't need information about your product, price or company, you use the codes to register directly your products with your distributor (e.g. Amazon, CD Baby, supermarkets, grocery stores, etc). They will link the information as well as price to the code for you.
If you sell products online you should only need the numbers, however if you sell through a distributor instead of sending the products directly, you may need to print the barcodes on stickers, which you can do with the images we provide you with your order, or by using our printing service.
Since this item is a digital download all sales are final. If unsure buy one, try it, and if you purchase at least 100 more we'll reimburse the first one.
Just ask on our contact page