So, I want to make simple clicker game with upgrade system, but it is very time consuming and inconvenient to write the cost per click and the price for the next upgrade manually, so I want to ask if there is any formula to create an upgrade system?
Make your own formula. If you want an upgrade cost to double, then you have a base cost, double it each time a level is bought. If you want a percent increase, then code that in. You can do any mathematical formula you want. There is no magical “one formula”. It’s whatever you want.