http://schema.org/Offer
http://schema.org/price

(originally relayed from a colleague, Matthias)

Fixed already:

• price field, can we say something clearer about localization (use of €, $ symbols, '.', ',' for decimal vs 1000s, @content?). e.g. $ is ambiguous
• we could point out '.' vs ',' are ambiguous (http://en.wikipedia.org/wiki/Decimal_mark#Hindu.E2.80.93Arabic_numeral_system).
• Maybe we should we just say "without using '.' or ',' for 1000s", and using '.' for decimals? We can also note that both Microdata and RDFa allow localised human-facing markup to say one thing, but an equivalent decimal value can be written in the @content="..." attribute.
• gtin. we should link to http://www.gs1us.org/about-gs1-us/media-center/press-releases/gtin-validation-guide.
• a way of indicating the main offer in a page ('mainEntity' use case?) would be useful. Fixed in Add a mainEntity property that relates a page to the main thing it describes + inverseOf mainEntityOfPage #301"

Open...

• can we say something about whether tax is included in price?
• also consider adding examples or shortcut properties that show how to describe related products via their gtin.
• show a product example for mainEntityOfPage - the problem is that a merchant's web-site contains multiple offers, the "main" one and typically related product/offers, but also offers for the same product by different sub-sellers." e.g. http://www.walmart.com/ip/Teenage-Mutant-Ninja-Turtles-2014-Blu-ray-Gift-Set-With-Figurines-Walmart-Exclusive-Widescreen/38234327
• see also notes below...