I'd get the Amethyst just because of the sale, but I'd throw in an Ella - especially if this is a first toy. If you haven't done anything penetrative before, I would actually not recommend any of those.
Ella's an okay size if you've had penetrative sex, but just throwing it out there since I don't know your background. Ella was my second dildo, but I wish she'd been my third. Awesome toy, but the hard silicone was very unforgiving at first.