Much that I enjoy tweeting the occasional 10,000yen melon photo, I don't enjoy the fact that fruit is so expensive compared to much of the rest of the world. Being a fan of all things fruity, I've built up some good 'hacks' for getting my fruit fix without need of extended credit:
Frozen raspberries from OK supermarket (for example)
Raspberries freeze very well, when you defrost them, they are almost the same as fresh raspberries
Frozen Fruit from Hanamasa
Hanamasa has some large bags of frozen Mangos, strawberries and mixed berries. Whilst they don't freeze as well as raspberries they are very well priced. For example 550G of cubed mango for about 600yen - this is enough for about 8-10 mango smoothies
Order raw almonds online from Amazon
I'm also a fan of raw almonds, but I've never seen more than a pitiful amount for sale in Tokyo that aren't roasted and salted. In my research the cheapest bulk sellers of almonds are on Rakuten, but shopping there is an excersize in extreme frustration, so I prefer to pay a little extra buying on amazon
These chaps are generally the most reasonably priced fruit, quite often one can find a small bunch for 100yen at smaller supermarkets or fruit merchants. Also Hanamasa occasionally sells a "Hand" of bananas (that's a bunch of about 20), for 300yen.
What are your fruit (and nut) tips and tricks in Tokyo?