P.S. - the price at launch was about 4 BTC ( $25k in BTC at the time of buying)...please make more research ...
You could measure your prices fixed in BTC, but for some reason I have a feeling you wouldn't have sold the watch for 7 BTC a month after the watch released.
Bitcoin has appreciated to where the 7 BTC price tag puts a premium that is over 4x the original price of the watch.