i think OP was suggesting you look at GoPro / Fitbit's filing documentation with the government, which publicly discloses these numbers.
i'll look for them and update this comment if i find them
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> We have recently begun to spend significant amounts on advertising and other marketing campaigns to acquire new users, which may not be successful or cost-effective.
> We have recently begun to spend significant amounts on advertising and other marketing campaigns, such as television, cinema, print advertising, and social media, as well as increased promotional activities, to acquire new users and we expect our marketing expenses to increase in the future as we continue to spend significant amounts to acquire new users and increase awareness of our products and services. In 2014 and for the three months ended March 31, 2015, advertising expenses were $71.9 million and $21.1 million, respectively, representing approximately 10% and 6% of our revenue, respectively. While we seek to structure our advertising campaigns in the manner that we believe is most likely to encourage people to use our products and services, we may fail to identify advertising opportunities that satisfy our anticipated return on advertising spend as we scale our investments in marketing, accurately predict user acquisition, or fully understand or estimate the conditions and behaviors that drive user behavior. If for any reason any of our advertising campaigns prove less successful than anticipated in attracting new users, we may not be able to recover our advertising spend, and our rate of user acquisition may fail to meet market expectations, either of which could have an adverse effect on our business. There can be no assurance that our advertising and other marketing efforts will result in increased sales of our products and services.
ALSO
> Revenue increased $474.3 million, or 175%, from $271.1 million for 2013 to $745.4 million for 2014. A substantial majority of the increase was due to an increase in the number of devices sold from 4.5 million in 2013 to 10.9 million in 2014, including $151.9 million from new products that we began selling in 2014. U.S. revenue, based on ship-to destinations, increased $356.5 million, or 173%, from $206.1 million for 2013 to $562.6 million for 2014 and international revenue, based on ship-to destinations, increased by $117.9 million, or 181%, from $65.0 million for 2013 to $182.9 million for 2014.
So ballpark 11 million units sold in 2014, and 71.9 million dollars in advertising in 2014
That's $6.59 worst case customer acquisition cost (assuming no repeat customers)
http://www.sec.gov/Archives/edgar/data/1447599/0001193125151...