Ads in emails from webshops that I purchased from in the past sometimes work, as long as: they don't send me such emails too frequently (i.e. not more than once

Ads in emails from webshops that I purchased from in the past sometimes work, as long as: they don't send me such emails too frequently (i.e. not more than once a week), and it is a shop from where I've actually purchased something in the past and not just spam. Ads on the web (and especially in mobile apps) usually have the reverse effect: it drives me away from using that site or application or to install an adblocker, and the ads I do see I use as a guidance on what NOT to buy.