Jean-Talon is pretty incredible when the market is full with vendors. During colder months, it is more or less empty. Many vendors offer samples. You can even ask to try a variety of something if you're unsure if you'll like it, and usually someone will be willing to slice into some produce to give you a try if they're not offering samples already. You can definitely get some great deals on farm fresh produce and also try some good pre-made food in the food stalls.