As much as one wants; to one's heart's content — a suffix meaning 'do something freely or without restriction', used after the -masu stem or volitional form (e.g. 食べ放題).
この店は夜まで飲み放題のプランがある。
This shop has an all-you-can-drink plan until night.
子どもたちは休日に遊び放題だった。
The children were free to play as much as they wanted on the holiday.
時間があるから、本を読み放題だ。
I have time, so I can read as many books as I like.