Possible Clues:

• Apparent worth
• *What a 'forever' stamp lacks
• It might not indicate true worth
• For Helen, a thousand ships not an excessive price
• Amount as printed or stamped on money or other object
• Terrific state entering Tube - really not worth it?
• Bond number
• Worth that's apparent in fine state, with exterior pipe
• What a statement might be taken at
• Apparent worth of clock prize