Telegram is great indeed. I'm happily paying for premium for two reasons: first it's not expensive at all (2€ per month) and secondly it offers so many fun and useful features. I often buy it for friends too as a gift. They really have a good thing going.

On most other platforms it's usually more the stick than the carrot (pay up or we bombard you with ads) and it's tons more expensive, eg Instagram alone costs 3x as much.