What was the price of Bitcoin when it closed at the end of the day on 2013/4/29?
price when it closed refers to close; on 2013/4/29 refers to date = '2013-04-29'
SELECT T2.close FROM coins AS T1 INNER JOIN historical AS T2 ON T1.id = T2.coin_id WHERE T2.date = '2013-04-29' AND T1.name = 'Bitcoin'