Does smudging have side effects?

Im currently in the process of moving and have 50 percent of my things in the apt already.After reading up on the internet about smudging with white sage I was ready to buy this 5 dollar smudging kit on ebay but my insticts made me feel wary about what if the person who created this advertised blessed sage is accually twisted and created it to be back.Evil in desquise type of thing.Anyway my first question is have you herd of side effects and 2.where can i buy white sage from a natural place.Not a psychic store.i also forget to mention the previous renters were drunk trouble makers who got evicted and im postive the place has negative energy that i dont want my baby to be living in