be on the breadline : very poor
ex : more people in Britain are on the breadline now than thirty years ago.
live in the lap of luxury : live an extremely comfortable life, because you have a lot of money
ex : We live simply during the year, but enjoy living in the lap of luxury in a nice hotel for our summer holiday.
well off / well-to-do / well-heeled : having plenty of money
ex : Most of the people living here are clearly very well-to-do, but there are a few poorer families.
spend money like water : spend too much, often without thinking about it
ex : He spends money like water.
tighten your belt : spend less than you did before, because you have less money
ex: I’m afraid we’ll have to tighten our belts now there’s another mouth to feed.
make a killing : earn a lot of money very easily
ex: The new internet companies have made an instant killing.
be a money spinner : be a successful way of making money
ex : My dog-walking business was quite a money spinner when I was at collage.
pay thorough the nose : pay a lot of money : 法外な代金を払う
ex : We had to pay through the nose to get our car repaired.
a small fortune : a lot of money
ex : We had to spend a small fortune on getting everything we needed for our holiday.