Agent provide data, and you do your home work, and decide the price.
But unfortunately, here is most chinese people do:
1. Let agent decide the price, and offer that price,
2. If accepted, immediately regret and feel you offered too high. 然後開始和seller/agent別扭, try everything to get even with the seller.
3. If rejected, immediately feel bad, regret you offered too low,
4. Blame the agent.
See this over and over again.