There's sites out there that search Home Depots inventory and let you know about penny deals

This YouTube video explains it in detail: How to Rob Home Depot for $0.01 Items (Penny Deal Reselling)

You signup to the site (sometimes free trials are available) then you search for the deals

Go to the store, buy them for $0.01 each. Flip on Offerup, eBay, Facebook marketplace 

Rinse/repeat