Height
noun
You've seen the word 高い from a couple levels ago. This word is related to that. It's like 大きい versus 大きさ, where one describes the other. In this case, the 高さ is the height of something (while 高い is tall). This word isn't "price" though. For that you'd ask いくらですか？ (how much is it?).
Use the reading of 高い (たかい) to help you to learn and remember the reading for this one. They're the same except for the hiragana at the end.
テーブルの高さ
height of the table
ビルの高さ
height of the building
どのくらいの高さ
how tall
あのアパートの高さは三十メートルです。
The height of that apartment is thirty meters.
ギャグセンの高さでは、どうしてもコウイチとマイケルには勝てないよ。
I can never beat Koichi and Michael when it comes to their level of humor.
ふじ山には、高さだけでなく、美しさもある。
Mt. Fuji has not only height but also beauty.