I don't have much experience in e-commerce, app installs. Our clients tend to be in home security, trade schools/education, and other high cost per lead areas. There were definitely fads in the past like daily deals and user acquisition for startups (fashion/chain restaurants). I'm sure some people are priced out as Facebook has gotten more expensive -- I think that happens with any platform (e.g. Google, display).

Yup! To give you insight from my end. I'm doing typically ~$200 baskets at anywhere between $3-10 per conversions.