noun
unlimited use; all-you-can-use
Often used in service plans, subscriptions, or promotions where a fixed fee allows unrestricted usage.
このアプリは月額500円で使い放題です。
This app is available for unlimited use at 500 yen per month.
使い放題プランに申し込むと、データ通信が無制限になります。
If you sign up for the unlimited plan, data usage becomes unrestricted.
無制限 is a more formal term meaning 'unlimited' or 'without restrictions', while 使い放題 is a common compound used in commercial contexts.
Compound of 使い (stem of 使う 'to use') + 放題 (suffix meaning 'as much as one likes').