knock back = cost
- The new furniture has knocked us back a lot of money.
- Your new car must have knocked you back a fortune.
- His education has knocked his family back many thousands of dollars.
- The apartment knocked me back a lot but it is worth it.
- How much did this piano knock you back?
- These bills will knock us back three hundred pounds.
- What a beautiful dress! That must have knocked you back a bit.
- This watch knocked me back 300 euros.