What is the worth of a double brick of buffalo nickels?

It's not possible to give a specific answer unless you know each coin's date, mint mark, and condition. The best that can be said is that common-date buffalo nickels in average condition have a retail price of about $1 each. Those without dates are considered culls and sell for 15-25 cents each. Better-condition and scarcer dates can sell for much more but each one is different.