If the lock unit's max current draw is 0.33A at 24V, then you could power at least nine of them from a 24V/3A supply. I say 'at least' because they're unlikely to all be drawing max demand at the same time. There should be a spec for quiescent current or something like that.
A typical 24V/3A DC supply could be powered by 115V at less than 15 amps, so it could be just plugged into a wall socket if it has a cord and plug, or one could be added.
We can't tell from here which catalog you're looking at.
Mike Halloran
Pembroke Pines, FL, USA