Would I be able to get braces or a retainer?

Not many of my teeth are wonky/crooked but the ones that are are at the front of my mouth and obviously show when I smile. My dentist said that I could be borderline braces, but he never said anything more and I was wondering if I could get a retainer instead and how much it would cost? It's only for 3 or 4 teeth and they are moderate, but the rest of my teeth are well aligned so I don't know about treatment.