I am building a free android app from which one can buy daily use items such as groceries. Users would have online payment options in app. Will Google play-store charge me per purchase/transaction made in app ? Im confused on what purchases are treated as in-app purchases and Service fees is applied.
I read this question but want to be specific on non digital content sale in app
The simple answer is no.
You can find information about it here: https://support.google.com/googleplay/android-developer/answer/9858738
Here are some examples of products not currently supported by Google Play In-App Billing according to the support page:
Retail merchandise, such as groceries, clothing, housewares and electronics. Service fees, including taxi and transportation services, cleaning services, food delivery, airfare and event tickets. One-time membership fees or recurring dues, including gym memberships, loyalty programmes or clubs offering accessories, clothing or other physical products. One-off payments, including peer-to-peer payments, online auctions and donations. Electronic bill payment, including credit card bills, utilities and cable or telecommunications services.