
1. Alemany Flea Market- Every(literally rain or shine) Sunday. This flea is more like a big freakin garage sale. Lots of junk and lots and lots of treasures. Prices can vary from dirt cheap to WTF. Alemany is a guaranteed score!
http://www.yelp.com/biz/alemany-flea-market-san-francisco
2. Candlestick Park Antiques & Collectibles Faire- Random weekends depending on 49ers schedule. If you are familiar with the Alameda Flea then this faire is a bit similiar to that. This one is not the massive size of the Alameda, but still a pretty decent day killer. Prices will be a bit higher than Alemany as many vendors are professional dealers....and they have their own website.
http://www.candlestickantiques.com/
3. Treasure Island Flea- Last weekend of the month(sat & sun). Honestly, I haven't been since it just opened last month. I think it caters to the likes of "all of the above." Lots of different vendors, and options of things to look at. Personally, I don't really like craft fairs, so I might wait to hear from someone who's been before I make the leap. If you are looking for a reason to go to Treasure Island then this would be an awesome reason! Awesome views all around!
http://www.treasureislandflea.com/index.html
In addition, multiple SF neighborhoods have pop up flea's on nice days! If you see one, then check it out cause you might find something really awesome!
GOOD LUCK!!!