keep in mind there are stainless and galvanized ones, different widths etc.
So that you know you're comparing the same ones
I usually just get them from the local industrial hose / hydraulics / etc store, as they'll sell singles.


Those 2-ear style clamps are not good on rubber hoses. They leave a loose spot that will eventually leak when the rubber loses elasticity.
Go for "stepless" 1-ear Oetiker clamps.
FYI, 1/2" PEX is 5/8" OD. So, if your hose is really 5/8" OD, you can go to the hardware store and pick up the Oetiker clamps made for PEX connections in a 10-pack for far cheaper than you'll pay for a large assortment.