To want something very badly; to be ready to go to extremes to reach one's goal

I'm fine, but I'd give my right arm to be twenty again

Sto bene, ma darei il braccio destro per tornare ad avere vent'anni

My grandma, a nice little old lady from the past, would have given her right arm for a mink coat. Times have definitely changed!

Mia nonna, una deliziosa vecchietta d'altri tempi, avrebbe dato il braccio destro per una pelliccia di visone. Altri tempi!

The right arm is a virtual necessity for the 90% of people who are right-handed. Being ready to sacrifice such an important part of your body for something, it means that this thing is extremely important for you