We know NAND gates are the cheapest gate to fabricate. There are ways to turn ANDS and ORs into NANDS
This comes naturally with Sums of Midterms since it’s a bunch of inputs ANDed together and those ANDs bunched into 1 OR; it satisfies that above scenario!
Sum-of-products = a layer of AND gates connected by an OR gate = can turn into NAND gates with De-Morgan’s Law / Bubble Pushing