Agree with Jimi that probably the most proper antonym for "free of charge" is "on the market." But, "procured" or "priced" could function as the alternative of "free of charge." This book is free of charge. This reserve is priced. That dessert was free of cost. That dessert was procured. https://googlemybusinessbacklinks93497.59bloggers.com/37206551/5-simple-statements-about-backlinks-with-high-da-explained