Am I expected to know Japanese to go to Japan?
I would encourage you, but would not force it. Keep in mind that most of the population has a "English Perfection Syndrome" and would not dare communicate in English. Most of the signs in the metro area are displayed in English, so getting around is not that big of a problem.
Do the people in the airport speak English?
They certainly do! And the staff at tourist spots are supposed to speak too.. I haven't tried them all yet.
I heard everything in Japan was expensive.
Generally, but not everything in Japan is expensive. If you go to famous tourist spots, you're more likely to be paying more than the locals do. I would bet that the locals are paying less money to eat than you are... Basically, tourists will get ripped off for not having enough information. For those with less information, here's a guide for a budget travel.
Would buying electronics in Japan be cheaper than in the US?
I think it won't be that much of a difference. Most importantly, you need to think about
product warranty. If you buy electronics in Japan, chances are you won't have warranty for it when you
bring it back to the States.
FYI, snacks are definitely cheaper than buying imported ones at Wegmans.
How much does Sushi cost?
The price will depend on how much quality you'd like it in. If you're OK with cheap, out-of-the-fridge, amateur taste, the lowest is around 100 yen per plate. If you're ready to take on the real ones (I mean the crazy ones), one plate can cost around 30,000 yen, which is USD300.
When is the best season to climb Mt. Fuji?
Summer is the best season, but is also the most popular season to climb Mt. Fuji. Dress warm though, as climbing at higher altitudes have colder temperatures than at ground level.
What are the legal ages for drinking, smoking, and driving?
20 to drink, 20 to smoke and 18 to drive.
Where can I find vending machines that sell nasty stuff?
To be honest, I've never seen one yet. You sure the photo wasn't photoshopped? And what's the point of buying nasty stuff from vending machines anyway?
Can you teach me some swear words?
Absolutely not. Here's the reason why: if all the Japanese language you knew consisted
of swear words, and spoke to a yakuza, you'll be in deep sh*t.