Worth in what sense? Catalog value? Retail price charged by a dealer to replace them? Wholesale amount that a dealer would pay you to buy and then resell them? And which plate number?--some are uncommon and carry a premium.
You can see retail prices, offered by a reputable dealer, starting at the following link. Be sure to look at the PS/5 ("plate strip of 5") column, and the correct plate number ("Pl #") that matches what you own.http://www.pnc3.com/prlt/prltpnc1891-2136.htm