New to diffusing essential oils

I got a diffuser for Christmas along with Flora Classique frankincense and pitchouli essential oils. I was told by some friends that this is an awful brand and the oils are trash. :( Is this true? I also have a 14 month old so I want to make sure these scents are safe to diffuse around him. my poor husband was trying to be nice by getting me all this but didn't know you have to get certain ones.

How big of a deal is it if I diffuse the cheap/not absolutely pure oils? (So long as they are scents that are safe for my little one) If it is completely necessary, what are some cheaper options for the "good" essential oil brands?