@Chris: And to clarify how it works, you get one swimsuit per Streetpass. Every swimsuit has a different design and three color schemes. The one I needed was 39 which has a cow print on it and has the center string tied into a circle instead of dangling. There are 50 Streetpass swimsuits total. I'm cheating a bit by Streetpassing myself using my old 3DS. I get 4 per day like this.