When do you start charging users? On the launch day or after some time?

Freemium model's popular - free tier to hook users, then upsell. But if your product's solid, don't be afraid to charge early (imho).

I think it depends on your product and target users. If you have high confidence in your product, you could start with a freemium model - offer core features for free to attract users and get feedback, while charging for advanced features. That lets you refine the product before going all-in on paid plans. But if your product really solves a valuable problem for businesses, an intro discount followed by full pricing could work to get paying customers from day 1. Experiment and see what fits your market! I'm also curious what's worked well for others.

I would start charging from day 1 but keep the pricing really low initially, like $5/month. Get some early users and revenue to validate the concept. Then as you get feedback and improve the product, gradually raise prices to a more sustainable level, grandfather in the early supporters, and consider having free and premium tiers. The key is to charge something from the beginning to qualify demand but stay flexible on pricing as you figure things out.