100 yen store in Machida

I've heard the largest 100 Yen store is in Machida. However, I can't seem to find that station. Is it the same as Machiya?

And where is harajuku station?

However, I can't seem to find that station. Is it the same as Machiya?

No, it is not the same station. Machida is a city in the western suburbs of Tokyo. It can be reached in 30 minutes from Shinjuku by Odakyu Railways.

And where is harajuku station?

On the Yamanote Line, 5 minutes south of Shinjuku:
http://www.japan-guide.com/e/e3006.html

To look up train routes:
http://www.jorudan.co.jp/english/norikae/

The largest ones are in Machida(Southern Tokyo Prefecture) and Funabashi(between central Tokyo and NRT). These 2 are the largest.

The one near JR Kinshicho station(3 stops from Akihabara) is also very large and conveniently located if you are in central Tokyo.

is Daiso Harajuku (a few steps from Harajuku Station) any good? And is it just as big as the one in machida?

Here is Giga store list.
http://www.daiso-sangyo.co.jp/english/storeinfo/storeinfo05....

Daiso Harajuku is nowhere near the size of the Giga stores. Machida and Funabashi are both around 6,600 sq. meters. The Harajuku location is only around 1,000 sq. meters.

You also have a 3rd option; which is not so far from Tokyo itself, which is the Tokyo arcakit store; which is just next to Kinshicho station. It has 3300 sq. meters and Kinshicho is just about 10 minutes away from Akihabara on the Sobu line, which can be ridden on Shinjuku.

yes