What is the value of a 1943 US silver penny?

First off, it's not silver, it's zinc-coated steel.* In average condition, it's worth 25 to 50 cents.

Copper was needed to make ammunition so the Mint switched to steel to save metal. It proved unsatisfactory due to rust and confusion with dimes, so copper coins were resumed in 1944.

(*) If you think about it for a minute, a cent is larger than a dime, so a true silver cent would have been worth about 15¢, which wouldn't have made any "cents" from a profit-and-loss perspective.