Tokyo on a shoestring budget
Tokyo is exciting but expensive. Space is at a premium. Accommodation will be your biggest expense.
The best way by far of staying in Tokyo on a shoestring is to have a local connection to stay with. Unfortunately it's not common for Japanese people to invite people home for visits much less to let people stay overnight. There is also a language barrier that can lead to uncomfortable miscommunication. And Japanese people are busy - it's not uncommon to have 10-12 hours wordkdays plus long commutes on a train.
A good way to make connections is to offer your home to Japanese guests using couchsurfing.org before your trip. After you have hosted Japanese in your home they will want to return the favor by offering to host you.
Join a Buddhist or Christian organization with Japanese members, Karma is alive and well. If you contribute to a community, they'll give back to you. You'll have a better chance of staying with a relative or Tokyo branch of the group.
Another way of saving on accommodation is by bike camping. Bicycle camping is gaining popularity. I brought my bike to Japan, camped most nights and was never hassled by anyone. We did take a few precautions. We always waited until dark to pitch our tent. And tore down our tent and packed at first daylight. .
Always lock your bikes, but theft is much less common than in North America.
One night a week you'll want to stay at the Tokyo Youth Hostel to do your laundry.
It's easy to get lost and not be able to find your way back to your gear. Be sure to lock-up near a landmark. I liked to use a train station. I always copied down the name of the station in Japanese characters so I could ask for directions back easily.
There are lots of cheap entertainment possibilities. It's all about finding the adventure in everyday stuff.
Standing bars (nomiyas) are Western style bars where you can buy a beer for a $3 or $4. You're more likely to find English-speaking Japanese here. Izakayas are traditional bars that offer cheap beer and food popular for office drinking parties.
Or just duck into any small shop with a red lantern outside to share a pint with the locals.
Barbecue on Shonan Beach. Grab a bag of charcoal some fish and veggies at a market close to the beach and have fun. Pull out you tent after dark and fall asleep to the sound of waves, If you hear a loud siren it means a typhoon or tsunami is coming.
Take the train to Kamakura to see the Giant Buddha, Go hiking around the city.
Get up early and visit Tsukiji fish market, the largest fish market in the world. Watch the local wholesalers haggle over tuna in the morning auctions.
Visit Ginza department stores check out the crazy prices on stuff.
To see more people than you've ever seen before, try walking through Shinjuku Station during rush hour,
Practice striking up conversations with the giggling ladies on the street, trains and coffee shops.
Check out all the latest gadgets in Electric Town and the Sony Building.
Beer vending machines are everywhere. Grab a seat in the closest park and soak up the Japanese ambiance.
Free Internet Access
You can gorge on free WiFi at many coffee shop chains.
Free Food and (Coffee Refills)
It's free samples galore in the basement food halls of many department stores.Hit the convenience stores for $1 rice balls and snacks. All the fast food chains are here too.
Most coffee shops and fast food restaurants don't offer free refills. Watch out for free refill signs behind the counter. Wendy's in Ginza is my favorite. Some branches of McDonalds are good for a second cup of java.
Free English Magazine
Tokyo Classified is free and lists upcoming events, movies and so on. You can pick it up from Tower Records in Shibuya.