If you are a procurement officer and purchased goods and the seller offer you a gift with the purchasing what will you do ???

Personally, no. I'm sure company have rules for these, but to be honest a lot of people do take the gift.  If you end up purchasing cost that is financial costly, your job and career might take a down turn. If you don't, enjoy that gift I guess.

Very simple. Ask the supplier to adjust double the value of the gift as a discount to the price he has offered for the good.

Refuse as its is unethical