Hot enough for you?
Here's the thing about farmers markets: you have to go there prepared to pay a lot of money. The modern incarnation of a once-per-week food festival bears little resemblance to what originally started as a place to do your weekly shop. Of course, farmers and other stall holders have to earn a living. But that doesn't change the fact that the market scene is not what it once was.
Back in Dublin, I used to visit the (usually) excellent Dun Laoghaire Farmers Market with my family. Aside from a coffee and a snack, there's little worth buying unless you have a special need to. Ok, a pack of organic eggs are better than what you might find in the supermarket and it's nice to have a fresh, home-made cake if you're expecting company. However, the really appeal of the modern farmers market is the chance to soak up the atmosphere and chat with the sellers who really care about their product.
Young couples and young families
I went to Aoyama Famers Market in Tokyo to see how it compared. Of course, this being Tokyo, I should have anticipated the large crowds and high prices. Nonetheless, despite the reasonably decent selection of produce on sale, I didn't really feel like waiting 10 or 15 minutes to be served at some of the more popular stalls. On the plus side, there were free samples a-plenty so if you like farmers markets but don't feel like spending a fortune, Aoyama Farmers Market is at least worth a visit.
Queues in front of almost every stand
In a different kind of long queue, one for refreshments
I don't want to jump to conclusions after only one visit, but I'd list Aoyama as a good place to start a day of Tokyo sightseeing and even worth a visit for locals. At the very least there are enough snack stalls to cater to everyone's tastes. Also of note is an area to adopt poorly-treated or abandoned dogs from shelters. It was so heart-warming to see encouraging their kids to connect with animals in this way rather than just going for the usual puppy or kitten.
Final purchases: lots of spicy peppers (see below), some fancy mushrooms (long gone)
This outing was only a medium level success,
so if anyone knows any other good Tokyo food markets let me know!