Please provide links to events for members who have paid more than 50 dollar.
have paid more than 50 dollar refers to cost > 50
SELECT DISTINCT T3.link_to_event FROM expense AS T1 INNER JOIN member AS T2 ON T1.link_to_member = T2.member_id INNER JOIN attendance AS T3 ON T2.member_id = T3.link_to_member WHERE T1.cost > 50