When you go into a store just to eat all of the free samples. It is similar to a shopping spree, except that you're looking for free samples instead of things to buy. This is mainly used as an easy way to get free food and annoy the hell out of the store at the same time.
John: Man, I'm SO BORED.
Jake: Dude, let's go on a sampling spree at Terribly Named Mart and see how long it takes for the employees to get mad at us.
John: Alright bro! Let's do it!