I have two Shopify stores, and for both I'm running some tests with Google Adwords.
I've set up both sites as e-commerce sites in Google Analytics.
Both sites are reporting the correct sales so the links to Shopify are working fine.
But when I look at the Google stats, for one site, I get a useful indication of revenue per key phrase (see LH of attached image).
But on the other I just see 'not set' (see RH of attached image).
I can't see any differences between how I've set up each of the links so I'm a bit baffled.