If your meeting is paid, you can change its price at any time from the meeting link's payment settings (see Accept payment online). Existing bookings and purchased packages are not affected. Here's what changes and what doesn't.
Sessions that are already booked
When someone books a paid meeting, the price they agree to is locked in for that booking. Changing the price later never changes what an existing booking is charged.
This also covers sessions that are charged later instead of at the time of booking. A recurring meeting, for example, can be set to charge before each session. Every one of those sessions is charged the price from when the booking was made, not the current price.
The new price applies only to bookings made after you save the change.
Packages a customer already bought
A package gives the customer a fixed amount at the moment they buy it, either a set number of bookings or a set amount of meeting time, depending on how the package is set up. Changing the package price, or what the package includes, does not change any package a customer has already bought. They keep exactly what they paid for.
The new price and settings apply only to packages purchased after you save the change.
So re-pricing a meeting link or a package is safe, only future bookings and future purchases pick up the new price.