You don't need anything except your bass, and maybe an amp and cable to connect the two, if you're into that sort of thing. Myself and a lot of other people - famous professionals, even - got by just fine without anything more than those three items for decades.
In my opinion, if one is unsure of why they might need an effect or what is used for, then they most likely have no use for it. It's much better (and cheaper!) to just play and develop an ear for what you might personally want to hear, than to use your eyes and let TB conversations dictates your needs.
Whew! I was beginning to think I was the only one who was left out in the cold.