• not to have a penny to one's name

• at the expense of it

• an eye-opener

• a pretty penny

• penny for your thoughts

• in penny numbers

• spend money like water

• in for a penny in for a pound

• not to cost a penny

• a penny for them

• the penny drops

• turn up like a bad penny

• spend a penny

• turn an honest penny

• go off the deep end

• two a penny

• penny wise and pound foolish

• a poison-pen letter

• be thrown in at the deep end