expensive, expansive

Expensive or expensive means costly, describing something that costs a lot of money--
The model we looked at yesterday is too expensive. This one is cheaper.
Are they taking an expensive vacation, or an inexpensive one?

Expansive or expansive describes a state of emotional openness, generosity, and lack of restraint--
His expansive characteristics are well withing the normal range.
When he drinks he becomes expansive, and sometimes gives away all of his money.

Now that you know that, you can say--
"His expansive episodes became so expensive that his family had him committed for observation."

Note--"expense" is a noun ( thing or idea ), meaning cost, or amount of money spent--
Just get the best one; spare no expense.
He is filling out the expense account report now.
The plural of "expense" is "expenses", meaning all of the money spent for a particular purpose--
Our expenses for this month are high.
His salary does not cover his living expenses.
"Expanse" means an uninterrupted stretch of something--
It was almost impossible to cross the vast expanse of desert in a single day.
Note # 2--"extensive" means large in scope, wide or broad--
The building will need extensive repairs.
He has an extensive knowledge of modern literature.