Possible Clues:

• Plenty
• Much first-rate upright timber
• Bargain for the most part
• There is plenty of such a satisfactory bargain
• A timber that's sound ehough to be quite a bargain, if there's plenty of it (1, 4, 4)
• It's a bargain and there's plenty of it (1, 4, 4)
• Most of this bargain is satisfactory
• What a bargain in sound timber
• What 17-, 25-, 36- or 50-Across is
• Very much in the past, occasional ale drunk