There are two compositions of pennies, the ones that are 95 percent copper, and the ones that are 97.5 percent zinc.
The US mint changed the composition of pennies during the 1982 mint year, so pennies older than 1982 are almost all copper, and worth, at current copper prices, about 2.3 cents apiece (
http://www.coinflation.com/). That's in theoretical melt value, which you cannot currently do under US law.
The zinc pennies are worth .5 cents in melt value.
If you anticipate high- or hyper-inflation at some point, copper prices will zoom; eventually, I believe, the US government would allow melting of older pennies to feed the market with copper stock.
Here's what I'd do if I were you:
Save all pennies. Separate them by year. Save the older ones; cash in the newer ones and buy silver with the proceeds.