I just so happen to live on the Rue d'Aligre. The market is on every morning apart from Monday, from around 8am till 1pm (2pm at the weekend).
Why is it so good? It's insanely cheap, it's right outside my door, there's a huge variety, the traders are super friendly, the street is lined with food shops and cafés for all your needs. There's also a covered market for expensive posh stuff, and bric à brac stalls on the Place d'Aligre.
The above haul set me back €4 this morning. Cheap enough for you?
Top tips for bargains: go on a Sunday, towards closing time; and head to the end of the street towards the Rue de Charenton, not the Rue du Faubourg St Antoine. Cheaper, less busy.
Dare to disagree? Have your own favourite market? Tell all!
Rue & Place d'Aligre
Métro: Ledru-Rollin (line 8) or Gare de Lyon (Lines 1 and 14)
Open Tuesday -Sunday, 8am - 1/2pm.