Should I save some money and buy a 50-pound bucket of powdered shock?

No. Powdered chlorine should be purchased in small, air sealed bags (or similar) so that each time one uses it, it is a “fresh” supply of chlorine. The large buckets seem economical when priced out “per pound” but each time one opens the large bucket of chlorine and gets a whiff of the chlorine gas, what we are smelling is the loss of the valuable chemical. Quite often by the time we get to the bottom of that bucket, there is very little chlorine left and all we are adding is binders and “chalk”. Purchase quality chemicals and it will pay off in the long run.