T.H.
Children's place sells the cutest ties for little boys. I bought one for my son and he looked adorable!! I would suggest since it's a formal event do slacks, a button down, and a tie. You really don't need a suit...he'll never wear it again by the time he grows out of it. They also send out tons of coupons so look for one of those before you shop! Macy's and Norstrom also have cute looks, as well as Baby Gap (one of my faves!) but the ties at Children's Place were the cutest and cheapest I found for little guys.