If someone is still assuming that whatsapp, FB, Insta are free and bought an chinese android phone just to use these apps, then they better switch back to 2G phones instead of upgrading to 5G phones later.
Already Youtube is pushing everyone to subscribe for Premium. Facebook has merged WhatsApp, Instagram data and has already sold it to other data mining companies. Also using them to 'serve you better ads'.
Gmail will not cost you anything because you either paid for Android or its already serving you Ads/promotions.
Soon, whatsapp business app will switch from a notification-based pricing model to a conversation-based pricing model. Businesses will be charged per conversation which includes all messages delivered in a 24 hour session.
Cost per conversation between $0.03 to$ 0.10 and businesses will levy these expenses on customers (you).
Random businesses in your area will start sending their business ads through whatsapp (It already started)