50# of cal hypo for $105 is good . . . IF it is this season's production. However pool wholesaler's often discount old chemical stock to try to get it out of their warehouses before the fumes become a problem!

You CAN shock with either calcium or sodium hypochlorite, but you'll be adding calcium to your pool, which may or may not be a problem.

But. . . Walmart is selling, in many parts of the country, a fresh 10% pool bleach that is being bottled at over 10%:
Pool-Essentials-Chlorinating-Liquid
At $3/gallon it's about the same cost per pound of chlorine-gas equivalent as the cal hypo. ($3.20/lb vs $3/lb Cl2 equiv)