How to repair a leaking aquarium?

I know how I'm going to go about fixing it so the real question is what type of silicone to use? I don't want to spend $5 on a tube from the pet store that won't last 2 minutes. Would home depot or Lowe's sell anything i could use? I've heard you can use any silicone as long as it don't have any additives , is that right?