I just picked mine up at Walmart in the aisle with nuts and bolts. It’s been over a year since I got them, but at that time they were always out or just had one or two packs. Home Depot was the same way, plus they had them in a weird spot which made it hard to find. Fortunately I was accumulating them way in advance, but it was still frustrating. Maybe buying online would be easier.
This is what Walmart has.