Take the urban and rural No.7 bus at Chengdu University of Technology (you should distinguish it from the No.7 bus) and go directly to the second-hand market.
From the direction of Shiling, you can take Urban-Rural No.3 Road to Longtan Industrial Park, get off and walk about 500 meters. ?
Is there one in Wugui Bridge? It is the largest flea market in Chengdu, just on the right side of the station? You'll know when you get there.