Where to purchase ignition coils, and how do I measure primary coil resistance on 1995 Chevrolet Lumina

One of my ignition coil packs is bad and needs replacing, where is the best place to go to buy a new one? There is an Auto Zone and Advanced Auto Parts store in town but I have been told in the past these are not the best places to buy electrical replacement parts.
The ignition coil pack is visually bad, one of the towers has carbon scoring and pitting. (The spark plugs and wires have already been replace.) Checking the resistance of the coils wasn't necessary, but I am having trouble checking the primary coil resistance. I understand where and how to check the primary coil resistance but the probes of my ohm meter do not fit into the slots, where the coil pack connects to the ignition module, to make a measurement.

Asked by for the 1995 Chevrolet Lumina
use the coils from autozone and such. they are fine