How to deal with a meltdown???

My son is 2 and completely had a meltdown in the store. We were trying ro get him to buy Christmas presents for people and he freaked out and threw a huge fit. Now we are home and hes screaming he wants to buy presents. How do you deal with kids public meltdowns??? Im at a loss, my husband just wants to spank him. He needs a spanking and got one, but what else can I do?

I don't need judgement about spankings. I spank my son on occasion when needed. Im not ashamed about it one bit.