Possible Clues:

• Where buyers are at a disadvantage (2 words)
• When prices jump or vault, it's said makers will be twitchy and tense
• Sounds like somewhere wine is sold when the dealing is at its most expensive (7',6)
• Where profit is likely
• Sound wine stores observe it — it's good for their trade
• Time of high prices
• Bad time to buy
• Where, by the sound of it, one might buy wine, even when the prices are high