I find that some fruit/veg stalls start offers even earlier than 3pm. If you keep an eye out you can definitely get some bargains. If you're into your booze, there's a good alcohol store with a wide variety of beers and ales from around the world.
If you've never been to the market, i recommend your first visit as a scouting exercise, as it's a lot to take in, and it can get quite crowded. If you go around lunchtime, you will inevitably succumb to the gorgeous smells and aromas of all those stalls serving up meat dishes. Yum.