個こ (kako)

リンゴを 6 個こ 買かってきてください

Please buy six apples.

おにぎり2個食べた。

I had two onigiri [rice balls].

何個も買っていいよ。

You can buy several of them.

2個目は半額だって。

Apparently the second one is half price. // It says the second one is half price.

おにぎり2個も食べた。

I had two whole onigiri [rice balls]!

携帯三個も持ってるの？

You have *three* cell phones?

トマト2個買ってきて。

Will you go pick up two tomatoes (at the store)?

まくら六個も使ってるの？

You use six pillows?

これ5個買ったらいくら？

How much would it cost if we bought five of these?

じゃがいも９個買ってきて。

Will you go pick up nine potatoes?

おにぎり2個しか食べてない。

I only had two onigiri [rice balls.]

まくら百個も必要ないでしょ。

You don't really need 100 pillows.