Yesterday my son took Skittles from Petsmart.?

Last night my 5 y/o son and I were in Petsmart. When we got home, he came upstairs and told me he "got Skittles from Petsmart and put them in his pocket" He had proceeded to dump them on his vanilla ice-cream. I asked him if he knew he was supposed to pay for something before we left the store and he said yes. I told him that was called stealing and I sent him to bed. I told him we were going to Petsmart again tonight after work/school and would be paying for the Skittles with money out of his piggy bank. I saved the wrapper so that they could ring it up, and I will have him apologize. Do you think this is the right thing to do?