Fig.: to be very expensive. To cost may be substituted by to pay

I work downtown and I use public transportation to get there because parking downtown would cost me a pretty penny

Lavoro in centro e per andarci uso i mezzi pubblici perché parcheggiare in centro mi costerebbe fior di soldi

Redoing all the landscaping will cost you big money, but the whole house will increase in value

Rifare completamente il giardino ti costerà fior di soldi, in compenso si rivaluta l'intera casa